Chop cherries in half, ensuring there are no stray pits.
In a medium bowl, stir together cherries, sugar, almond extract, lemon juice, and tapioca. Let sit while you make the crust.
Crust/Crumb Topping
Preheat oven to 350°F. Spray an 8 x 8-inch square baking dish with cooking spray, then line with parchment paper, allowing the parchment to extend past the sides for easy lifting.
Mix together flour, oats, brown sugar, and baking powder.
Add melted butter and almond extract. Mix until well combined.
Stir in chopped pecans.
Press half of the mixture into the bottom of the prepared pan. Set aside the remaining half.
Pour cherry mixture over the crust.
Sprinkle the remaining oat-pecan mixture on top of the cherries. Do not press down; this is a loose crumb topping.
Bake
Bake for 37-40 minutes or until the cherry juices are slightly bubbly and the oat mixture is turning a golden brown.
Cool completely before serving to allow the cherry juices to settle into the crust.
Once cool, cut into 12 squares and enjoy on their own or with ice cream. The bars will keep for several days in the fridge and are, in my opinion, even better the next day.
Notes
You can use frozen cherries; do not thaw before using. Fresh cherries are the star of these bars.
Swap the pecans for walnuts or slivered almonds if preferred.