Preparation

Make the crumbs

• Preheat the oven to 375ºF. Grease the inside of a 10-inch round springform pan.Combine the peanut butter, flour, brown sugar, and peanuts in a mixing bowl. Work the mixture between your fingers to form large crumbs. Refrigerate until ready to use.

Make the cake

• Whisk together the eggs, milk, and vanilla in a large measuring cup.Combine the flour, baking powder, and salt in a medium mixing bowl.

  Combine the butter and sugar in a large mixing bowl and cream with an electric mixer on medium-high until fluffy, scraping down the sides of the bowl as necessary. With the mixer on low speed, slowly add the egg mixture and mix until well combined. Add the flour mixture, 1/2 cup at a time, scraping down the sides of the bowl after each addition.

  Scrape the batter into the prepared pan and smooth the top with a rubber spatula. Place the jam in a small bowl and whisk until loosened and spreadable. Use a small offset spatula to spread the jam over the batter. Break the peanut butter mixture up into large crumbs with your fingers and drop them over the jam. Bake the cake until it is golden and a toothpick inserted in the center comes out clean, 40 to 45 minutes. Let the cake cool in the pan for about 10 minutes. Release the sides of the pan and use a large spatula to slide the cake from the pan bottom to a wire rack. Cool completely, cut into wedges, and serve.

Make Ahead Tips

Store uneaten cake in a cake keeper or wrap in plastic and store at room temperature for up to 2 days.