Homemade Peach Crumb Bars

Crumble:

• cooking spray
• 1 ½ cups all-purpose flour
• ½ cup white sugar 
• ½ teaspoon baking powder
• 1 pinch salt
• 10 tablespoons unsalted butter, cold, cut into cubes
• 1 large egg yolk
• 1 tablespoon cold water

Filling:

• 2 cups sliced fresh peaches, or more to taste
• ½ cup white sugar 
• 2 tablespoons all-purpose flour
• 1 tablespoon fresh lemon juice
• 1 teaspoon vanilla extract
• ¼ teaspoon ground cinnamon 
• ¼ teaspoon ground nutmeg

1. Preheat the oven to 375 degrees F (190 degrees C). Coat an 8-inch square baking pan with cooking spray.
2. Whisk 1 ½ cups flour, ½ cup sugar, baking powder, and salt together in a large bowl; cut in cold butter using 2 forks or a pastry cutter until mixture resembles coarse crumbs. Slowly mix in egg yolk and cold water; dough should be very crumbly. Press ½ crumble mixture into the prepared pan; reserve remaining ½ crumble mixture.
3. Combine peach slices, ½ cup sugar, 2 tablespoons flour, lemon juice, vanilla, cinnamon, and nutmeg in a separate bowl; spread over crust and top with reserved crumble mixture.
4. Bake in the preheated oven until golden brown and set, 30 to 38 minutes. Cool to room temperature, then cut into 12 bars.