Rich Peanut Butter Cup Dump Cake

The kitchen was quiet except for the hum of the oven, and I found myself standing there with a box of cake mix and a jar of peanut butter, wondering what would happen if I just let them do their thing together. Sometimes the best desserts come from that place of curiosity and a little bit of laziness, where you dump everything in a pan and see what magic unfolds forty minutes later.

I brought this to a friends potluck last summer and watched three different people ask for the recipe, their expressions shifting from skeptical to absolutely delighted after that first bite. Theres something about warm peanut butter and chocolate that makes people forget their table manners and go back for seconds, standing around the pan with forks in hand.

Ingredients

• Devils food chocolate cake mix: Using a box mix here is absolutely fine—the secret is what you add to it and the peanut butter layer underneath
• Creamy peanut butter: Make sure its at room temperature so it spreads evenly across the bottom of the pan without tearing
• Unsalted butter, melted: Salted butter works too but you might want to reduce the added salt if your peanut butter already has plenty
• Whole milk: The fat content helps keep the cake tender and moist, though you can get away with lower fat milk in a pinch
• Mini peanut butter cups: The size matters here—full-sized cups would be too overwhelming and wouldnt distribute as evenly
• Semi-sweet chocolate chips: These balance the sweetness of the peanut butter and cake mix perfectly

Instructions

Get your oven ready:

Preheat to 350°F and grease a 9x13-inch baking dish—I like to use butter instead of spray because it adds another layer of flavor that complements the peanut butter

Spread the peanut butter foundation:

Drop spoonfuls of room temperature peanut butter across the bottom of the dish and gently spread it into an even layer, taking care not to tear through to the bottom

Whisk together the cake batter:

In a large bowl, combine the cake mix, melted butter, and milk, whisking just until combined—those small lumps will disappear in the oven

Layer the batter:

Pour the chocolate batter over the peanut butter layer, spreading it gently so the two layers remain distinct

Add the toppings:

Scatter the mini peanut butter cups and chocolate chips across the surface, pressing them in slightly so they dont roll off

Bake until perfectly set:

Bake for 35 to 40 minutes until the cake is set and a toothpick comes out with moist crumbs but not wet batter

Let it rest before serving:

Cool for at least 15 minutes so the peanut butter layer has time to set up slightly, though serving it warm is absolutely worth it

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My sister called me after making this for her book club, slightly breathless, insisting that she had to make another one the next day because the first pan disappeared in under ten minutes. Thats the thing about recipes like this—they become part of your rotation not because theyre impressive but because theyre devastatingly good in the most uncomplicated way possible.

Making It Your Own

The beauty of a dump cake is that it forgives almost any modification you throw at it. Ive swapped in almond butter when peanut allergies were a concern, added a layer of crushed pretzels for salt and crunch, and even topped it with marshmallows during the last five minutes of baking for a fluffernutter situation that had my kids begging for it weekly.

Serving Suggestions

Warm with vanilla ice cream is non negotiable at my house—the cold cream against that warm peanut butter chocolate situation is exactly why dessert exists. But Ive also served it cold for breakfast the next morning, standing at the counter with a fork and zero regrets, and honestly it might be even better that way.

Storage and Make Ahead Tips

This actually keeps remarkably well, which surprised me given how gooey it is fresh from the oven. The flavors meld overnight and the texture settles into something more fudgelike, making it excellent for making a day ahead of a party or for those moments when you need emergency dessert at 9pm.

• Wrap the cooled pan tightly with foil and it will sit happily on the counter for two days
• Refrigerate it if you prefer a firmer texture or if your kitchen runs warm
• Warm individual slices in the microwave for 20 seconds to recreate that fresh baked experience

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Sometimes the most unpretentious recipes are the ones that find their way into regular rotation, the ones you can make without thinking, the ones that show up at every gathering and make people genuinely happy. This is one of those.

Recipe FAQs

→ Can I use natural peanut butter instead of creamy?

Natural peanut butter can work, but it may affect the texture. The oils might separate during baking, creating a slightly different consistency. For best results, use standard creamy peanut butter with stabilizers.

→ Should I serve this warm or at room temperature?

Both ways are delicious! Warm servings highlight the gooey peanut butter cups and soft cake texture. Room temperature or chilled portions offer cleaner slices and a fudgier consistency.

→ Can I make this in advance?

Absolutely! This tastes even better the next day as flavors meld. Store covered at room temperature for 2 days or refrigerate for up to 5. Warm individual portions in the microwave for 20-30 seconds if desired.

→ What type of chocolate chips work best?

Semi-sweet chocolate chips provide balanced sweetness, but milk chocolate chips work if you prefer a sweeter profile. Dark chocolate chips add sophistication and complement the rich peanut butter beautifully.

→ Can I use a different size baking dish?

A 9x13-inch pan is ideal for the proper thickness. Using a smaller pan may require longer baking time, while a larger pan could result in thinner layers. Adjust baking time accordingly and check for doneness.

→ Why is my cake still wet in the middle?

The peanut butter layer remains somewhat fudgy even when fully baked. A few moist crumbs on your toothpick are normal. If significantly wet, continue baking in 5-minute intervals until set.