Summer Berry Crumble Bars – Simmer + Sauce

Ingredients

• 1 1/2 cups all-purpose flour
• 3/4 cup sugar, divided
• 1/2 teaspoon baking powder
• Pinch of salt
• 1/2 cup cold unsalted butter, small cubes
• 1 large egg, lightly whisked
• 2 cups fresh strawberries, hulled and diced
• 1 cup frozen wild blueberries
• 1/2 tablespoon cornstarch
• 2 teaspoons vanilla extract