Preheat oven to 350°F (175°C) and prepare a 9x13-inch baking pan with parchment paper or grease it.

In a mixing bowl, combine 2 cups of all-purpose flour, 1/2 cup of powdered sugar, and a pinch of salt. Cut in 1 cup of cold, softened butter until the mixture resembles coarse crumbs. Press into the bottom of the prepared pan.

Bake the crust for 15-20 minutes until lightly golden. Let cool slightly.

In another bowl, whisk together 3 eggs, 2 cups of granulated sugar, 1/2 cup of flour, and 1/2 teaspoon of baking powder. Fold in 3 cups of diced rhubarb.

Pour the filling over the cooled crust and bake for 40-45 minutes until set and lightly golden.

Allow to cool completely in the pan before slicing into squares. Enjoy!