Preheat oven to 350°F (175°C) and line the baking pan with parchment paper.
In a bowl, mix flour, sugar, baking powder, and salt.
Cut in cold butter until mixture turns crumbly.
Add egg and vanilla; mix into a soft dough.
Press ⅔ of dough into the pan for the base.
In another bowl, toss strawberries with lemon juice, vanilla, sugar, and cornstarch.
Spread strawberry mixture over the dough base.
Crumble remaining dough on top and bake for 35 minutes.
Let cool before cutting.
