For the Base:
1 cup all-purpose flour
1/4 cup sugar
1/2 cup quick oats
3 tbsp butter
For the Topping:
1 egg white
1 cup sugar
3 tbs flour
1/4 tsp baking powder
Pinch of salt
Juice and zest of 1 large lemon
Confectioner's sugar, sifted, for sprinkling
Preheat oven to 350 degrees. Coat an 8-inch square baking pan with nonstick cooking spray. Combine flour, oats and sugar in a medium bowl. Using a pastry blender, add butter and blend until the mixture is crumbly.
Press crumbs into the bottom of the baking pan. Bake for 10 minutes until edges are golden.
Meanwhile, whisk egg and egg white. Add sugar and beat until creamy. Add flour, baking powder, salt and lemon; whisk until smooth.
Pour lemon mixture over pre-baked base. Bake for 20-25 minutes, or until center is set.
Cool in pan for 15 minutes, then transfer to wire rack to cool completely.
Makes 16 squares.