How to Make It
Preheat oven to 375°F. Lightly grease an 8-inch square metal baking pan. Line baking pan with parchment paper, allowing 3 inches excess to hang over sides of pan.
Combine peanut butter, softened butter, granulated sugar, and 1/4 cup of the brown sugar in a medium bowl. Beat with an electric mixer on medium speed until creamy and fluffy, 1 to 2 minutes. Beat in vanilla until incorporated. Whisk together 1/2 cup of the flour, baking soda, and salt in a small bowl. Gradually add flour mixture to peanut butter mixture, stirring until fully incorporated.
Press dough firmly into bottom of prepared baking pan, being sure to press dough into corners of pan. Bake in preheated oven 15 minutes. Remove from oven, and press down dough with a wooden spoon or spatula. Return to oven, and bake at 375°F until set, about 10 minutes.
Remove crust from oven, and spread evenly with jam. Combine crumbled cookies, melted butter, and remaining 1 tablespoon each brown sugar and flour in a medium bowl. Stir until crumbled cookies are well coated. Sprinkle mixture evenly over jam. Return to oven, and bake until lightly golden, 12 to 15 minutes.
Cool in pan on a wire rack 15 minutes. Using parchment paper as handles, lift cookie mixture from pan, and place on wire rack to cool completely, 45 minutes to 1 hour. Remove and discard parchment, and cut into 9 squares.