1. Preheat your oven to 350°F (175°C) and line an 8×8 inch baking dish with parchment paper.
2. In a large bowl, whisk together the flour, granulated sugar, baking powder, and salt.
3. Add the cold, diced butter into the flour mixture. Using a pastry cutter or your fingertips, work the butter into the flour until it resembles coarse crumbs.
4. In a separate bowl, mix the beaten egg, heavy cream, and vanilla extract until well combined.
5. Pour the wet ingredients into the dry ingredients and gently fold until a dough forms. Be careful not to overmix.
6. Press half of the dough evenly into the prepared baking dish, creating a firm base.
7. Layer the sliced strawberries evenly over the dough base and sprinkle with powdered sugar.
8. Take the remaining dough and crumble it over the strawberries, pressing lightly to adhere.
9. Bake in the preheated oven for 25-30 minutes, or until the top is golden brown and the strawberries are bubbling slightly.
10. Allow the bars to cool in the pan for at least 15 minutes before slicing. This step is crucial to ensure clean cuts and to let the flavors meld together beautifully.

Remember, patience is key, just like my abuela taught me when I was rolling tortillas by her side. Letting the bars cool will enhance their texture and flavor.