Preheat oven to 350°F and line a 9x9 pan with parchment.
Mix filling ingredients; set aside.
Cut together butter, flour, sugar, baking powder, salt, and vanilla until crumbly.
Add egg; mix gently.
Press ⅔ of crust into pan.
Add filling.
Sprinkle remaining crust on top.
Bake 35–45 min, until bubbly and golden.
Cool before slicing.
