Preheat Oven to 350°F (175°C). Grease a 9x13-inch baking dish and line it with parchment paper, leaving overhang for easy lifting.
Prepare the Crust: In a large mixing bowl, combine flour, sugar, baking powder, and salt. Add cubed butter and, using a pastry cutter or your fingers, work it into the dry ingredients until the mixture resembles coarse crumbs.
Add Egg and Vanilla: In a small bowl, whisk together the egg and vanilla extract. Pour it into the crust mixture and mix until it just comes together. Set aside 1 cup of the crust mixture for the topping, and press the rest firmly into the bottom of the prepared baking dish.
Make the Cherry Filling: In a medium bowl, combine cherries, sugar, cornstarch, lemon juice, and almond extract. Stir until the cherries are evenly coated and slightly juicy.
Assemble and Bake: Spread the cherry filling over the crust in an even layer. Sprinkle the reserved crust mixture on top, covering the cherries but leaving some fruit visible for a rustic look.
Bake for 45-50 Minutes until the top is golden and the cherry filling is bubbling. Let the bars cool completely in the pan before lifting them out with parchment paper and slicing into squares.