Preheat your oven to 350°F. While it heats, finely dice the crystallized ginger into 1/8-inch pieces—this small size ensures the ginger distributes evenly throughout the pie without any large, overpowering chunks. In a small bowl, combine the diced ginger with 2½ tablespoons of sugar and grind or mash them together gently with the back of a spoon to help release the ginger's oils and create a more cohesive mixture. Cut the rhubarb into 1-inch thick slices and set aside.

In a large bowl, combine the rhubarb with the ginger-sugar mixture from Step 1. Add the brown sugar, flour, cinnamon, and salt, then gently toss everything together until the rhubarb is evenly coated and the flour is distributed throughout—this helps prevent clumping in the filling. I prefer to fold rather than vigorously stir, which keeps the rhubarb pieces intact and prevents the filling from becoming too juicy from bruised fruit.

Pour the filling from Step 2 into the pie crust, spreading it evenly. Place the pie in the preheated 350°F oven and bake for 65–75 minutes, until the filling is bubbling around the edges and the crust is golden brown. The filling should bubble visibly at the edges—this indicates the starches are fully gelatinized and the pie will have the right consistency when cooled.

Remove the pie from the oven and let it cool on a wire rack for at least 2–3 hours before slicing. This cooling time is essential—it allows the filling to set properly so each slice holds together beautifully. Serve with vanilla ice cream, which perfectly complements the tartness of the rhubarb and warmth of the ginger.