Preheat oven to 375 degrees and grease a 8x8 inch pan or line with parchment paper.
FOR THE CRUST:
Whisk together the flour, sugar, baking powder, and salt. Cut in the butter with a fork until mixture is crumbly. Mix in the egg and vanilla. *Note: If you're using a food processor you can just add everything to the food processor and pulse until crumbly. Then add in the egg and vanilla and process until combined.
Press half of the mixture into the prepared pan. Reserve the other half for later.
FOR THE Strawberries: Toss strawberries with lemon juice and vanilla extract. Sprinkle with the sugar and cornstarch. Toss to coat.
Spoon strawberries over the bottom crust discarding the liquid at the bottom of the strawberries. Sprinkle reserved dough on top of strawberries.
Bake for 35-45 minutes or until topping is lightly browned. Cool completely and cut into bars. Store in the refrigerator but I like to serve closer to room temperature.