Heat your oven to 350°F and grease a loaf pan (approximately 9x5 inches) with butter or non-stick spray, then line the bottom with parchment paper for easy removal. This prevents sticking and ensures your finished bread releases cleanly.

While the oven preheats, slice the rhubarb into 1/2-inch pieces and quarter the strawberries, then set aside. In a separate bowl, whisk together the coconut flour, baking powder, salt, cinnamon, and nutmeg until well combined and no lumps remain. This ensures even distribution of leavening agents and spices throughout the bread.

In a large bowl, cream together the melted and cooled butter, cream cheese, and sugar substitute until smooth and well combined. Add the vanilla extract and mix to incorporate. This combination creates a rich, smooth base that will support the eggs and other ingredients.

Add the room temperature eggs one at a time to the wet mixture, beating well after each addition until fully incorporated before adding the next. Using room temperature eggs helps them emulsify better with the other ingredients, creating a smoother, more cohesive batter. This step takes about 3-4 minutes total.

Add the dry ingredient mixture from Step 2 to the wet batter and fold together gently with a spatula until just combined—don't overmix, as this can develop the flour and make the bread dense. Once mostly combined, fold in the sour cream by hand until the batter is smooth and fully incorporated. I find sour cream adds wonderful moisture and tang to this bread, so don't skip it.

Gently fold the rhubarb and strawberries from Step 2 into the batter until evenly distributed, being careful not to crush the fruit. Pour the batter into the prepared loaf pan and smooth the top with a spatula. I like to arrange a few extra rhubarb pieces on top for a nice presentation and extra tartness in each bite.

Bake at 350°F for 65-75 minutes until a toothpick inserted into the center comes out with just a few moist crumbs (not wet batter). The top should be golden brown. Remove from the oven and let cool in the pan for 15 minutes, then turn out onto a wire rack to cool completely before slicing. This cooling time allows the crumb structure to set properly.