Peanut Butter Chocolate Sheet Cake
If there’s one dessert that can make anyone stop in their tracks, it’s a chocolate and peanut butter combination done right. And let me tell you, this Peanut Butter Chocolate Sheet Cake is exactly that. I recently made this cake for my boyfriend’s birthday, and let me just say—it was a hit. Not only did he rave about it, but his entire family couldn’t get enough. There’s something magical about seeing everyone’s eyes light up with that first bite, and this cake brought exactly that moment to life. Honestly, if you’re a fan of Reese’s peanut butter cups, this dessert is basically a giant, sliceable version of your favorite candy—just in cake form.
From the moment I started baking, I could already imagine how indulgent this would be. Rich, moist chocolate cake layers paired with creamy peanut butter buttercream, finished with a glossy chocolate ganache, and topped with chopped Reese’s peanut butter cups—it’s basically a chocolate-peanut butter lover’s dream come true. And the best part? It’s completely doable at home. You don’t need to be a professional baker to make this show-stopping dessert; a little care, patience, and love is all it takes.
Making this cake for my boyfriend’s birthday reminded me why I love baking so much. It’s not just about the dessert itself—it’s about sharing something homemade, decadent, and full of love with the people who matter most. Watching him (and everyone else!) light up with every bite was the ultimate reward.
If you’re a fan of chocolate and peanut butter (and honestly, who isn’t?), this Peanut Butter Chocolate Sheet Cake is going to be your new favorite indulgence. It’s rich, decadent, and loaded with flavor, yet easy enough to make at home. Perfect for birthdays, celebrations, or just because—you really can’t go wrong.
So go ahead: grab some Reese’s cups, whip up that buttercream, and get ready to impress. This cake doesn’t just taste amazing—it makes moments unforgettable.
Ingredients
For the chocolate cake:
- 3 large eggs, room temperature
- 1 cup buttermilk, room temperature
- 1 cup hot brewed coffee
- ½ cup vegetable oil (or any neutral oil)
- 2 cups all-purpose flour
- 1½ cups granulated sugar
- ¾ cup unsweetened cocoa powder
- 2 tsp baking soda
- 2 tsp baking powder
- 2 tsp salt
- 2 tbsp vanilla extract
For the peanut butter buttercream:
- 1 cup unsalted butter (2 sticks), room temperature
- ¾ cup creamy peanut butter (I used Jif)
- 4½–5 cups powdered sugar, sifted
- ¼ cup heavy cream
- 2 tsp vanilla extract
- 1 tsp salt
For the chocolate ganache:
- 1 cup semi-sweet chocolate chips or chopped chocolate
- ½ cup heavy cream
Optional toppings:
- 8–10 full-size Reese’s peanut butter cups, chopped
- 4 mini reese’s peanut butter cups for the corners
Directions
1. Make the chocolate cake:
Preheat your oven to 350°F. Grease and line a 9×13-inch pan with parchment paper. In a large bowl, whisk together the flour, sugar, cocoa, baking soda, baking powder, and salt. In another bowl, whisk together the eggs, buttermilk, oil, and vanilla until smooth.
Pour the wet ingredients into the dry and whisk until mostly combined. Slowly add the hot coffee, whisking until the batter is smooth and glossy. Don’t worry if it’s thin—that’s exactly how it should be. Pour the batter into your prepared pan and bake for 30–35 minutes, or until a toothpick inserted in the center comes out mostly clean. Let it cool completely before frosting.
There’s something so comforting about the smell of this chocolate cake baking in the oven. It fills the kitchen with warmth and nostalgia—like birthdays, celebrations, and little moments of indulgence all rolled into one.
2. Make the peanut butter buttercream:
In the bowl of a stand mixer fitted with the paddle attachment, beat the butter and peanut butter together until smooth and fluffy, about 2–3 minutes. Add in the powdered sugar one cup at a time, alternating with heavy cream. Mix in the vanilla and salt, then beat for another 2–3 minutes until light, smooth, and spreadable.
This frosting is the kind of thing that makes you want to grab a spoon and sneak a taste before it even touches the cake. Creamy, fluffy, and packed with peanut butter flavor—it’s the perfect complement to the rich chocolate cake.
3. Make the chocolate ganache:
Combine the chocolate and heavy cream in a microwave-safe cup. Microwave in 20–30 second intervals, stirring in between, until fully melted. Let it sit at room temperature for 5–10 minutes, then stir again until smooth. The glossy, rich ganache adds a decadent finishing touch that makes this cake feel extra special.
4. Assemble the cake:
Carefully cut the cooled cake in half horizontally using a cake cutter. Spread a generous layer of peanut butter buttercream on the bottom half, then place the top half of the cake over it. Pour the chocolate ganache over the top, letting it gently drip down the sides. Pipe additional peanut butter buttercream around the sides and corners if desired, and sprinkle with chopped Reese’s peanut butter cups and mini cups.
Honestly, this part is pure joy. Seeing the layers come together, the ganache glistening, and those little chocolate-peanut butter treasures on top—it’s practically impossible not to smile.
Tips & Tricks
- Coffee in the cake: Don’t worry, it won’t taste like coffee. Instead, it enhances the chocolate flavor, making the cake extra rich and moist.
- Make ahead: Bake the cake a day in advance if needed. Keep it tightly covered at room temperature, then frost and assemble the day you want to serve it.
- Optional toppings: Reese’s cups aren’t just decoration—they’re a fun, crunchy, peanut-buttery addition that makes the cake even more irresistible.
Bake Ahead & Storage
One of the best things about this cake is that it’s actually very forgiving when it comes to timing—you can make parts of it ahead of time and still have it taste freshly baked. Here’s how I like to do it:
Bake Ahead:
- The chocolate cake itself can be baked 1–2 days in advance. Once it’s fully cooled, wrap it tightly in plastic wrap and store it at room temperature.
- You can also make the peanut butter buttercream ahead of time. Keep it in an airtight container in the fridge for up to 3 days. Before using, let it come to room temperature and give it a quick whisk to get it fluffy again.
- The chocolate ganache can be made a few hours ahead and stored at room temperature. If it firms up too much, simply microwave it for 10–15 seconds and stir until smooth before pouring over the cake.
Storage After Assembling:
- Once assembled, this cake keeps beautifully at room temperature for 1–2 days. Keep it covered loosely with a cake dome or plastic wrap to protect it.
- If you want to store it longer, cover tightly and refrigerate for up to 5 days. Allow it to come to room temperature before serving to get that perfect, soft texture.
- Leftovers can also be frozen: wrap individual slices in plastic wrap and foil, and freeze for up to 2 months. Thaw overnight in the fridge before enjoying.
