For the Pastry Dough:
1½ cups all-purpose flour
¼ cup granulated sugar
¼ teaspoon salt
½ cup cold unsalted butter, cut into ½-inch cubes
For the Peanut Butter Filling:
1 cup unsalted butter, at room temperature
1 cup creamy peanut butter
1 cup chunky peanut butter
1¾ cups powdered sugar
½ teaspoon vanilla extract
For the Crumb Topping:
¾ cups all-purpose flour
½ teaspoon baking powder
¼ teaspoon baking soda
¼ teaspoon salt
¼ teaspoon cinnamon
1/3 cup dark brown sugar
2/3 cup traditional rolled oats
6 tablespoons cold unsalted butter, cut into ½-inch pieces
2 cups jelly or preserves
1. Make the Pastry Dough: Butter the sides and bottom of a glass or light-colored metal 9x13-inch pan. Line the bottom with parchment paper, using enough parchment to hang over the sides of the pans. Put the flour, sugar and salt in a food processor and pulse until combined. Add the butter and pulse until sandy (about 6 to 10 quick pulses). In a small bowl, whisk the egg and pour into the food processor. Pulse just until the dough begins to hold together.
2. Dump the dough mixture into the prepared pan. Using your fingers, press the mixture into the bottom of the pan and up the sides just a little (maybe a half inch). Place the pan in the freezer for 30 minutes.
3. Preheat the oven to 375 degrees F.
4. Remove the pan from the freezer, line it with aluminum foil, and fill it three-quarters full with pie weights or dried beans. Bake for 15 minutes, then remove the foil and weights and bake for another 10 minutes, or until the crust is lightly browned. Transfer the pan to a wire rack to cool.
5. Reduce the oven temperature to 325 degrees F.
6. Make the Peanut Butter Filling: In the bowl of a standing mixer fitted with the paddle attachment, beat the butter until it is completely smooth. Add the peanut butter and beat until combined. Add the powdered sugar and vanilla and beat until smooth. Scrape down the sides of the bowl and beat again. Turn the mixture out onto the cooled crust and, using an offset spatula, spread it into an even layer. Put the pan in the refrigerator to chill while you prepare the crumb topping.
7. Make the Crumb Topping: In a large bowl, whisk together the flour, baking powder, baking soda, salt and cinnamon. Add the brown sugar and use your hands to rub it in until the mixture is uniform in color. Stir in the oats.
8. Place the dry mix in the bowl of a standing mixer fitted with the paddle attachment. Add the butter and beat on low speed until loose crumbs form.
9. Assemble the Bars: Spread the jelly in an even layer over the peanut butter filling. Sprinkle on the crumb topping, covering the jelly.
10. Bake the bars for 20 to 25 minutes, rotating the pan halfway through, or until the top is brown.
11. Transfer the pan to a wire rack to cool completely, then cut the bars and serve.
12. The bars can be stored in the refrigerator in an airtight container for up to 2 days.