Moist Rhubarb Instant Pot Cake

Finding a way to use up springtime rhubarb without turning on your oven can feel like an impossible task, especially when you’re already dealing with warm weather and a kitchen that heats up fast. And let’s be honest, traditional rhubarb desserts often require long baking times and careful temperature monitoring, which isn’t exactly ideal when you’re short on time or patience.

That’s where this rhubarb Instant Pot cake comes to the rescue: it’s perfectly moist and flavorful, cooks in a fraction of the time, and keeps your kitchen cool while still delivering that classic rhubarb cake experience you’re craving.

SAVE NOW

What Kind of Rhubarb Should I Use?

Fresh rhubarb is your best bet for this cake, and you’ll find it in grocery stores during spring and early summer when it’s in season. The color of the stalks doesn’t really matter – some rhubarb is bright red while other varieties are more green or pink, and they all taste pretty much the same. Just make sure to trim off any leaves if they’re still attached, as those are toxic and shouldn’t be eaten. If fresh rhubarb isn’t available, frozen rhubarb works too – just don’t bother thawing it first, as it can get mushy, and you might need to add a couple extra minutes to your cooking time.

SAVE NOW

Options for Substitutions

This cake is pretty forgiving when it comes to swaps, so here are some options if you need them:

• Rhubarb: Fresh rhubarb works best, but if you only have frozen, that’s totally fine. Just thaw it first and drain any excess liquid before using. You can also mix rhubarb with strawberries for a classic combo – use about 1 cup rhubarb and 1/2 cup strawberries.
• Yogurt: Sour cream or buttermilk both work great as substitutes. If using buttermilk, the cake might be slightly lighter in texture, which isn’t a bad thing at all.
• Cardamom: Not everyone keeps cardamom in their spice cabinet. You can skip it and increase the cinnamon by 1/2 teaspoon, or use a pinch of ginger instead for a different warm spice note.
• Brown sugar: Regular white sugar works if that’s what you have. The topping will be slightly less rich and caramel-like, but still tasty.
• Butter: You can use coconut oil in place of butter for a dairy-free version. Just make sure it’s melted and cooled slightly before mixing with the other ingredients.

Watch Out for These Mistakes While Baking

The biggest mistake when making Instant Pot cakes is skipping the paper towel under the foil, which leads to condensation dripping onto your cake and creating a wet, unappetizing top – always place a paper towel between the pan and foil to absorb moisture.

Another common error is not greasing your pan well enough or forgetting to line it with parchment paper, making it nearly impossible to flip the cake out cleanly after cooking.

Don’t rush the natural release time either, as opening the valve too early can cause your cake to sink in the middle or become dense instead of light and fluffy.

Finally, make sure your rhubarb pieces are cut into similar sizes so they cook evenly, and if your rhubarb is particularly juicy, pat it dry with a paper towel before mixing it with the brown sugar to prevent excess liquid from making the bottom layer runny.

SAVE NOW

What to Serve With Rhubarb Cake?

This rhubarb cake is perfect on its own with a cup of coffee or tea for an afternoon snack, but it really shines when you add a dollop of whipped cream or a scoop of vanilla ice cream on top. The warm spices like cinnamon and cardamom pair beautifully with a drizzle of caramel sauce or even some Greek yogurt if you want to keep things a bit lighter. I love serving this cake for brunch alongside fresh berries and maybe some scrambled eggs to balance out the sweetness. If you’re having guests over, a dusting of powdered sugar on top makes it look extra nice without any extra effort.

Storage Instructions

Store: This rhubarb cake stays moist and delicious when covered tightly with plastic wrap or stored in an airtight container at room temperature for up to 2 days. If you want to keep it longer, pop it in the fridge where it’ll last for about 5 days.

Freeze: You can freeze individual slices wrapped in plastic wrap and then placed in a freezer bag for up to 3 months. This way you can grab a piece whenever you’re craving something sweet without having to thaw the whole cake.

Serve: Let refrigerated or frozen slices sit at room temperature for about 20-30 minutes before serving. If you prefer it warm, microwave individual slices for 15-20 seconds, and that buttery brown sugar topping gets all gooey again.

Estimated Nutrition

Estimated nutrition for the whole recipe (without optional ingredients):

• Calories: 2100-2250
• Protein: 24-28 g
• Fat: 110-120 g
• Carbohydrates: 270-290 g

Ingredients

For the cake:

• 3/4 cup butter (I like Kerrygold unsalted butter for this)
• 1 cup sugar
• 2 eggs
• 1 egg yolk
• 1/2 cup yogurt (use full-fat Greek for a much moister crumb)
• 3/4 tsp vanilla essence
• 1 1/2 cups flour (I always use King Arthur all-purpose flour)
• 1 1/2 tsp baking powder
• 1 1/4 tsp cinnamon
• 1/2 tsp salt
• 3/4 tsp cardamom
• 1/2 tsp nutmeg

For the topping:

• 1/3 cup butter (melted and cooled to room temperature)
• 1/2 cup brown sugar (I prefer Domino light brown sugar)
• 1/2 tsp cardamom
• 1 1/2 cups rhubarb (sliced into 1/2-inch thick pieces)
• 1/2 tsp lemon zest

Step 1: Prepare Pan and Gather Equipment

• butter
• 1 cup water
• steamer rack

Grease a 7-inch round cake pan (or similar 6-8 cup capacity pan) generously with butter, then line the bottom and sides with parchment paper—this ensures easy removal after cooking.

Set the pan aside.

Fill your Instant Pot with 1 cup of water and place the steamer rack inside, then preheat the pot on the sauté setting while you prepare the batter.

This head start helps the pressure build faster once the pan is sealed.

Step 2: Make the Cake Batter

• 3/4 cup butter
• 1 cup sugar
• 2 eggs
• 1 egg yolk
• 1/2 cup yogurt
• 3/4 tsp vanilla essence
• 1 1/2 cups flour
• 1 1/2 tsp baking powder
• 1 1/4 tsp cinnamon
• 1/2 tsp salt
• 3/4 tsp cardamom
• 1/2 tsp nutmeg

In a large mixing bowl, cream together 3/4 cup butter and 1 cup sugar until light and fluffy, about 2-3 minutes.

Add the 2 eggs, 1 egg yolk, 1/2 cup yogurt, and 3/4 tsp vanilla essence, mixing until fully combined.

In a separate bowl, whisk together 1 1/2 cups flour, 1 1/2 tsp baking powder, 1 1/4 tsp cinnamon, 1/2 tsp salt, 3/4 tsp cardamom, and 1/2 tsp nutmeg.

Fold the dry mixture into the wet ingredients until just combined—I recommend using a spatula and folding gently rather than overmixing, which keeps the crumb tender and moist.

Step 3: Prepare the Rhubarb Topping

• 1/3 cup butter
• 1/2 cup brown sugar
• 1/2 tsp cardamom
• 1 1/2 cups rhubarb
• 1/2 tsp lemon zest

In a small bowl, combine 1/3 cup melted butter (cooled to room temperature), 1/2 cup brown sugar, 1/2 tsp cardamom, 1 1/2 cups rhubarb sliced into 1/2-inch pieces, and 1/2 tsp lemon zest.

Stir gently until the rhubarb is well coated.

The cooled butter prevents the eggs from curdling if it comes into contact with them, and the lemon zest brightens the tart rhubarb flavor beautifully.

Step 4: Assemble Cake in Pan and Prepare for Cooking

• rhubarb mixture from Step 3
• cake batter from Step 2
• paper towel
• aluminum foil

Pour the rhubarb mixture into the prepared pan and spread it evenly across the bottom—the rhubarb will sink slightly, which is perfect.

Gently pour the cake batter from Step 2 over the rhubarb layer and spread it to an even thickness with a spatula.

Cover the top of the pan with a paper towel, then place a sheet of aluminum foil over it, creating a tight seal that prevents condensation from dripping onto the cake during pressure cooking.

Step 5: Pressure Cook the Cake

• prepared pan from Step 4
• Instant Pot with water and steamer rack

Cancel the preheating sauté setting on the Instant Pot.

Carefully place the covered pan onto the steamer rack inside the pot using a sling (folded aluminum foil or a silicone sling makes this easier).

Seal the lid and set the Instant Pot to cook on high pressure for 60 minutes.

Once the cycle completes, allow the pressure to release naturally for 10 minutes, then carefully move the pressure valve to release any remaining pressure manually.

Step 6: Release and Remove Cake

• cooked cake in pan from Step 5

Using oven mitts or tongs, carefully remove the hot pan from the Instant Pot and place it on a heat-safe surface.

Remove the foil and paper towel covering.

Run a thin knife around the edges of the pan to loosen the cake from the sides, then place a serving plate over the top of the pan.

With confidence, flip the pan and plate together so the cake inverts onto the plate, revealing the beautiful caramelized rhubarb on top.

Let the cake rest for 5 minutes before slicing—this helps it hold together better.

Moist Rhubarb Instant Pot Cake

Delicious Moist Rhubarb Instant Pot Cake recipe with step-by-step instructions.

Print Recipe Pin Recipe

Prep Time 30 minutes mins

Cook Time 1 hour hr

Total Time 1 hour hr 30 minutes mins

Servings 8 slices

Calories 2175 kcal

Ingredients

  

For the cake

• 3/4 cup butter (I like Kerrygold unsalted butter for this)
• 1 cup sugar
• 2 eggs
• 1 egg yolk
• 1/2 cup yogurt (use full-fat Greek for a much moister crumb)
• 3/4 tsp vanilla essence
• 1 1/2 cups flour (I always use King Arthur all-purpose flour)
• 1 1/2 tsp baking powder
• 1 1/4 tsp cinnamon
• 1/2 tsp salt
• 3/4 tsp cardamom
• 1/2 tsp nutmeg

For the topping

• 1/3 cup butter (melted and cooled to room temperature)
• 1/2 cup brown sugar (I prefer Domino light brown sugar)
• 1/2 tsp cardamom
• 1 1/2 cups rhubarb (sliced into 1/2-inch thick pieces)
• 1/2 tsp lemon zest

Instructions

 

• Grease a 7-inch round cake pan (or similar 6-8 cup capacity pan) generously with butter, then line the bottom and sides with parchment paper—this ensures easy removal after cooking. Set the pan aside. Fill your Instant Pot with 1 cup of water and place the steamer rack inside, then preheat the pot on the sauté setting while you prepare the batter. This head start helps the pressure build faster once the pan is sealed.
• In a large mixing bowl, cream together 3/4 cup butter and 1 cup sugar until light and fluffy, about 2-3 minutes. Add the 2 eggs, 1 egg yolk, 1/2 cup yogurt, and 3/4 tsp vanilla essence, mixing until fully combined. In a separate bowl, whisk together 1 1/2 cups flour, 1 1/2 tsp baking powder, 1 1/4 tsp cinnamon, 1/2 tsp salt, 3/4 tsp cardamom, and 1/2 tsp nutmeg. Fold the dry mixture into the wet ingredients until just combined—I recommend using a spatula and folding gently rather than overmixing, which keeps the crumb tender and moist.
• In a small bowl, combine 1/3 cup melted butter (cooled to room temperature), 1/2 cup brown sugar, 1/2 tsp cardamom, 1 1/2 cups rhubarb sliced into 1/2-inch pieces, and 1/2 tsp lemon zest. Stir gently until the rhubarb is well coated. The cooled butter prevents the eggs from curdling if it comes into contact with them, and the lemon zest brightens the tart rhubarb flavor beautifully.
• Pour the rhubarb mixture into the prepared pan and spread it evenly across the bottom—the rhubarb will sink slightly, which is perfect. Gently pour the cake batter from Step 2 over the rhubarb layer and spread it to an even thickness with a spatula. Cover the top of the pan with a paper towel, then place a sheet of aluminum foil over it, creating a tight seal that prevents condensation from dripping onto the cake during pressure cooking.
• Cancel the preheating sauté setting on the Instant Pot. Carefully place the covered pan onto the steamer rack inside the pot using a sling (folded aluminum foil or a silicone sling makes this easier). Seal the lid and set the Instant Pot to cook on high pressure for 60 minutes. Once the cycle completes, allow the pressure to release naturally for 10 minutes, then carefully move the pressure valve to release any remaining pressure manually.
• Using oven mitts or tongs, carefully remove the hot pan from the Instant Pot and place it on a heat-safe surface. Remove the foil and paper towel covering. Run a thin knife around the edges of the pan to loosen the cake from the sides, then place a serving plate over the top of the pan. With confidence, flip the pan and plate together so the cake inverts onto the plate, revealing the beautiful caramelized rhubarb on top. Let the cake rest for 5 minutes before slicing—this helps it hold together better.