1. Preheat oven to 325°. Mix flour, sugar, baking powder, and salt in a large bowl.
2. Whisk melted butter, egg, and vanilla in another basin; add to flour mixture and stir. Press into a greased 13x9-inch baking dish.
3. For the topping, mix cream cheese and eggs in a large bowl until smooth. Add confectioners' sugar and mix.
4. Pour on crust. Bake 40–45 minutes until the center is almost firm and the edges golden. Cool for 1 hour on a wire rack. Add more confectioners' sugar if desired.