Makes:18 (3-by-1-1/2-inch) bars
The classic combo of peanut butter and jelly tastes great in a sandwich, so why not baked into a chewy bar cookie for dessert? Mix rolled oats and chunky peanut butter into a crumble that does double duty as both the bottom crust and a sweet, nutty topping. In between, spread a thick layer of chunky strawberry jam that’ll bake into a bubbly, fruity filling. These sweet comfort-food bars are perfect to wrap up for a lunch box treat or stow in a picnic basket.
1/2 cup chunky all-natural peanut butter (no salt or sugar added)
10 tablespoons unsalted butter (1 1/4 sticks), cut into small pieces and at room temperature, plus more as needed
1 cup chunky strawberry jam
Heat the oven to 350°F and arrange a rack in the middle. Coat a 9-by-9-inch metal baking pan with butter, then flour, tapping out any excess flour; set aside.
Place the measured flour, oats, sugars, salt, and baking soda in a large bowl and whisk to combine. Add the peanut butter and, using your fingers, squeeze the oat mixture and peanut butter together until evenly combined. Scatter the measured butter pieces over the mixture and, using your fingers, squeeze the peanut butter–oat mixture and butter together until evenly combined and no large pieces of butter remain.
Place two-thirds of the mixture into the prepared pan and, using a measuring cup dipped in flour, press it firmly and evenly into the bottom; set the remaining mixture aside. Bake until the edges start to brown, about 15 minutes.
Remove the pan from the oven to a wire rack. Dollop the jam over the crust and spread into an even layer, taking care not to disturb the crust. Crumble the reserved oat mixture into pieces about the size of almonds and evenly sprinkle it over the jam. Return the pan to the oven and bake until the jam is bubbling and the topping is golden brown, about 20 to 25 minutes more.
Remove the pan to the wire rack and let it cool completely, about 1 1/2 hours. Cut into 18 (3-by-1-1/2-inch) bars.