Mix together butter, 2 cups flour, and 1/2 cup confectioner’s sugar with an electric mixer. Press into the bottom of a 9x13-inch baking dish.
Bake for approximately 15 minutes, or until lightly golden brown.
Pineapple Squares Filling:
Mix together eggs, sugar, pineapple tidbuts including their juices, 1 cup flour, baking powder, and cornstarch until well combined. Pour over the baked crust.
Place into the oven and bake until set, about 25 minutes.
Remove from oven and allow to cool slightly. Dust with 1/4 cup confectioner’s sugar.