Step 1

Preheat the oven to 375 degrees F (190 degrees C). Grease a 9x13-inch baking pan.

Step 2

Stir 1/2 cup white sugar and cornstarch together in a medium bowl. Mix in 1 cup sliced strawberries at a time.

Step 3

Combine flour, remaining 1/2 cup white sugar, brown sugar, baking powder, cinnamon, and salt in a large bowl. Stir in melted butter and egg with a fork until crumbly.

Step 4

Press 1/2 of the crumble mixture into the prepared pan. Cover with strawberry mixture, then top with remaining crumble mixture.

Step 5

Bake in the oven until golden brown, about 45 minutes. Remove from the oven and let cool to room temperature, about 20 minutes. Place in the refrigerator before slicing into 16 bars.