Buttery Blueberry Crumble Bars Recipe

Ingredients

• 2 cups blueberries (about 250-300 grams if using fresh)
• 2 teaspoons cornstarch (use 4 teaspoons if using frozen berries)
• 1 tablespoon lemon zest
• 1 tablespoon lemon juice, freshly squeezed
• 1/4 cup granulated sugar (50 grams)
• 1 and 1/2 cups all-purpose flour (188 grams)
• 1/2 cup granulated sugar (100 grams)
• 1/2 teaspoon baking powder
• 1/4 teaspoon salt
• 3/4 cup unsalted butter (170 grams), cold and cubed
• 1 large egg yolk
• 1 tablespoon packed brown sugar
• 1 tablespoon granulated sugar
• 1 tablespoon all-purpose flour