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Crockpot Chocolate Peanut Butter Cake - Easy, Rich, and Foolproof

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Prep Time 15 minutes
Cook Time 3 hours
Total Time 3 hours 15 minutes
Servings: 8 servings
Ingredients Method

Ingredients
  

  • For the cake base: 1 box (15.25 oz) chocolate cake mix (devil’s food or dark chocolate)
  • 3 large eggs
  • 1/2 cup vegetable oil (or melted butter)
  • 1 cup milk (or water for a lighter texture)
  • 1 teaspoon vanilla extract
  • For the peanut butter layer: 3/4 cup creamy peanut butter
  • 1/3 cup powdered sugar
  • 2 tablespoons milk (to loosen for swirling)
  • 1/2 teaspoon vanilla extract
  • For extra richness (optional but recommended): 1 cup semi-sweet chocolate chips
  • 1/2 cup peanut butter chips or chopped peanut butter cups
  • To finish: Sea salt flakes (a pinch, optional)
  • Vanilla ice cream or whipped cream for serving
  • For the crockpot: Cooking spray or butter for greasing
  • Parchment paper sling (optional, for easy lift-out)

Method
 

  1. Prep the crockpot: Lightly grease the insert with cooking spray or butter. If you like, line the bottom with a parchment sling to help lift the cake out later.
  2. Mix the cake batter: In a large bowl, combine cake mix, eggs, oil, milk, and vanilla. Stir until smooth and no dry streaks remain. Fold in the chocolate chips if using.
  3. Make the peanut butter swirl: In a small bowl, whisk peanut butter, powdered sugar, milk, and vanilla until smooth and pourable. Add a splash more milk if it’s too thick.
  4. Assemble: Pour the cake batter into the greased crockpot. Spoon the peanut butter mixture over the top in several dollops. Use a butter knife to gently swirl it into the batter—don’t overmix.
  5. Add toppings: Sprinkle peanut butter chips or chopped peanut butter cups over the surface for extra pockets of flavor.
  6. Cook low and slow: Cover and cook on Low for 2.5 to 3.5 hours, or on High for 1.5 to 2 hours. The cake is done when the edges are set and a toothpick inserted in the center comes out with moist crumbs (a bit of melted chocolate is fine).
  7. Rest the cake: Turn off the heat, uncover slightly to vent, and let it sit for 15–20 minutes. This helps it set and makes serving cleaner.
  8. Serve: Scoop warm into bowls, top with a pinch of sea salt and a scoop of vanilla ice cream or whipped cream.