When the butter is cool, add it to your mixing bowl, add in the brown sugar and the granulated white sugar and cream until fluffy. Add in the egg, the egg yolk, and the vanilla and beat until fully incorporated.
In a separate bowl whisk together the flour, baking powder, and salt. Add the dry mixture to the wet mixture and fold until well incorporated. fold in the chopped up strawberries, and pour the batter into the parchment-lined baking pan.
Using a spatula, spread the batter evenly so that it is in every corner. Arrange the strawberries cut side down over the batter. (check out the notes to see how you can cut the perfect heart-shaped strawberries)
Bake for 30 to 35 minutes or until a toothpick inserted in the center comes out with just a few crumbs. The edges will look well baked and firm, the center will moist but not too gooey. Cool in the pan for 15 minutes then transfer it to a wire rack using the excess parchment paper as handles to get it out. When it is completely cool, drizzle with some white chocolate and cut it into 16 square pieces. Enjoy!