01 - Preheat oven to 350°F. Line a 9x13-inch baking pan with parchment paper, allowing edges to overhang for easy removal.
02 - In a large bowl, combine flour, oats, granulated sugar, brown sugar, baking powder, and salt. Mix thoroughly until evenly distributed.
03 - Pour melted butter and vanilla extract over the dry ingredients. Stir until the mixture becomes crumbly and all components are evenly moistened.
04 - Measure out and reserve 1 ½ cups of the crumb mixture for the topping. Press the remaining mixture firmly and evenly into the bottom of the prepared pan to form the crust base.
05 - In a separate bowl, combine halved cherries with sugar, cornstarch, lemon juice, and almond extract. Toss until cherries are evenly coated with the mixture.
06 - Spread the coated cherry mixture evenly over the pressed crust. Sprinkle the reserved crumb topping uniformly across the cherries.
07 - Bake for 35-40 minutes until the topping becomes golden brown and the cherry filling bubbles around the edges.
08 - Allow the bars to cool completely in the pan. Use the parchment overhang to lift the entire batch out, then cut into individual bars before serving.