Step 1

Preheat oven to 375 °F.  Line a 9×9-inch square pan with aluminum foil, then lightly grease.

Step 2

Make the shortbread crust. Add the flour, sugar, and salt to the bowl of a food processor and pulse several times to combine.  Add the butter and continue to pulse in short, one second bursts, until the mixture resembles coarse sand.  (Alternatively: whisk together ingredients and cut butter into the dough with two knives.)

Step 3

Set aside approximately 3/4 cup of the shortbread crust mixture. Spread the remaining shortbread crust into the prepared pan, pressing the crumbly dough down with a heavy glass, until dough forms an even layer across the pan.  Bake for 12 minutes, then remove from the oven.

Step 4

Make the fruit filling. While the crust bakes, prepare the filling. In a large bowl, mix together the halved cherries, cornstarch, lemon juice, and sugar. Spread the cherry filling over the crust.

Step 5

Top with crumb topping. Crumble the rest of the remaining shortbread crust dough over the top of the cherries, trying to get an even layer across the filling.

Step 6

Bake the pie bars. Return the baking pan into the oven and bake until the filling is bubbling and the crumb topping is golden, 25 to 30 minutes.

Step 7

Let bars cool fully in the pan and cut into bars before serving.