01 - Preheat oven to 350°F. Line a 9x13-inch baking pan with parchment paper, allowing overhang on sides for easy removal later.
02 - In a large bowl, whisk together flour, oats, granulated sugar, brown sugar, baking powder, and salt until thoroughly combined.
03 - Pour melted butter and vanilla extract over the dry ingredients. Stir with a spatula until the mixture is evenly moistened and crumbly.
04 - 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.
05 - In a separate bowl, combine cherries, sugar, cornstarch, lemon juice, and almond extract. Toss until the cherries are evenly coated.
06 - Spread the cherry filling evenly over the crust. Sprinkle the reserved crumb mixture generously over the cherries.
07 - Bake for 35 to 40 minutes until the topping is golden brown and the cherry filling is bubbling around the edges.
08 - Let cool completely in the pan. Use the parchment overhang to lift the bars out, then cut into squares and serve.