Preheat oven to 350°F (175°C). Line your baking pan with parchment paper.
In a bowl, mix flour, sugar, baking powder, and salt.
Cut in cold butter until the mixture becomes crumbly.
Add egg and vanilla extract; mix to form a soft dough.
Press 2/3 of the dough into the baking pan to form the base.
In another bowl, toss chopped strawberries with lemon juice, vanilla, sugar, and cornstarch.
Spread strawberry mixture evenly over the dough base.
Crumble the remaining dough on top and bake for 35 minutes until golden. Let cool before cutting.