Easy Peanut Butter Cake with Peanut Butter Frosting Recipe

This easy peanut butter cake with peanut butter frosting is a classic Texas sheet cake made in a 15 x 10-inch jelly-roll pan. The thin, tender cake takes just 18–22 minutes to bake, and the warm peanut butter frosting is spread over the cake before it cools for a smooth, creamy finish.

Every bite combines a soft peanut butter cake with rich, buttery frosting and just enough sweetness to make it irresistible. With about 24 servings and approximately 45–55 minutes from start to finish, this is a practical dessert for potlucks, birthdays, bake sales, holidays, or an ordinary afternoon craving.

Why You’ll Love This Recipe

This peanut butter sheet cake has the comfort-food appeal of a homemade snack cake but the easy serving style of a classic party dessert. Baking it in a jelly-roll pan creates a thin cake with plenty of surface area for generous frosting in every square.

The cake is tender rather than dense, thanks to buttermilk and the carefully heated butter mixture. The warm frosting settles into the top while the cake is still slightly warm, creating a soft layer that firms up beautifully as it cools.

• Quick preparation: The batter comes together in about 20 minutes.
• Party-friendly yield: One pan makes about 24 servings.
• Big peanut butter flavor: Peanut butter is included in both the cake and frosting.
• Simple presentation: Slice the frosted cake into squares and serve.

If you enjoy rich peanut butter desserts, you may also like these peanut butter fudge brownies for another bake-sale favorite.

Ingredients You’ll Need

The cake begins with pantry staples: all-purpose flour, granulated sugar, baking soda, salt, butter, water, eggs, buttermilk, vanilla, and creamy peanut butter. Heating the butter, water, and peanut butter together helps distribute the fat and peanut flavor evenly through the batter.

For the frosting, use unsalted butter, creamy peanut butter, milk, vanilla, and sifted powdered sugar. Sifting is helpful because it makes the warm frosting smoother and reduces the chance of stubborn sugar lumps.

• Peanut butter: Regular creamy peanut butter is the best choice for reliable texture.
• Buttermilk: It adds tenderness and balances the sweetness.
• Jelly-roll pan: A greased and lightly floured 15 x 10-inch pan gives the cake its classic thin shape.
• Optional variation: A 9 x 13-inch pan can be used, but the cake will be thicker and may need a few extra minutes to bake.

For a smaller peanut butter treat, keep our easy four-ingredient peanut butter cookies in mind.

How to Make It Step-by-Step

Step 1: Heat the oven to 375°F (190°C), then grease and lightly flour a 15 x 10-inch jelly-roll pan. Coating the pan carefully helps the thin cake release cleanly after cooling.

Step 2: Add the flour, sugar, baking soda, and salt to a large bowl and whisk until evenly combined. This distributes the leavening and salt before any liquid is added.

Step 3: Place the butter, water, and peanut butter in a saucepan and heat until the butter and peanut butter melt into a smooth mixture. Keep the heat moderate and avoid a vigorous boil, which can make the mixture unnecessarily hot.

Step 4: Pour the warm peanut butter mixture into the dry ingredients and stir until mostly combined. The batter may look thick at this point, but the egg and buttermilk mixture will loosen it.

Step 5: In a separate bowl, whisk together the eggs, buttermilk, and vanilla. Add them to the batter and mix just until smooth, taking care not to overmix.

Step 6: Spread the batter evenly into the prepared pan, using a spatula to reach the corners. Bake for 18–22 minutes, checking for a center that springs back lightly and a toothpick with only a few moist crumbs.

Step 7: While the cake bakes, prepare the frosting by heating the butter, peanut butter, and milk in a saucepan until melted and smooth. Remove it from the heat and stir in the vanilla.

Step 8: Gradually beat or whisk the sifted powdered sugar into the warm peanut butter mixture. If the frosting is too thick to spread, add milk a teaspoon or two at a time.

Step 9: Spread the frosting over the cake while the cake is still warm. Allow the frosted cake to cool before slicing so the topping can set and the squares hold their shape.

Pro Tips for the Best Peanut Butter Cake

The most important timing detail is frosting the cake while it is warm. Warm cake allows the frosting to glide across the surface without tearing the delicate crumb, while the frosting itself settles into a smooth, slightly fudgy layer.

Watch the cake closely near the end of the baking window. Since this is a thin sheet cake, it can dry out quickly if left in the oven after the center is set.

• Measure flour by spooning it into a measuring cup and leveling the top.
• Use room-temperature eggs and buttermilk when possible for an even batter.
• Stir only until the batter is smooth to protect the cake’s tender texture.
• Spread the batter to an even thickness so the edges and center finish at nearly the same time.
• Keep the frosting warm enough to spread, but remove it from the heat before adding the powdered sugar.

For a festive cookie tray, pair slices of this cake with our peanut butter Christmas sugar cookies.

Serving, Storage & Pan Options

Let the cake cool fully before cutting it into squares with a sharp knife. Wipe the blade between cuts for cleaner edges, especially once the frosting has set.

Store leftover cake covered at room temperature for a short period or refrigerate it for a firmer frosting layer. Bring refrigerated portions toward room temperature before serving so the cake becomes soft and buttery again.

If you use a 9 x 13-inch pan, expect a thicker cake and allow a few extra minutes if needed. Test the center rather than relying only on the clock, since pan depth and material can affect baking time.

For another easy dessert with a completely different fruit-forward profile, try this easy pineapple lush cake.

Flavor Variations and Decorating Ideas

The classic version needs no decoration beyond its creamy frosting, but a few simple finishing touches can make the squares look especially inviting. Add a light scattering of chopped peanuts after frosting, or leave the surface smooth for a polished bakery-style appearance.

• Sprinkle finely chopped roasted peanuts over the warm frosting.
• Add a very small pinch of flaky salt for contrast.
• Cut the cake into smaller bites for a dessert buffet.
• Serve each square with a glass of cold milk or a cup of coffee.

Keep additions modest so they do not overpower the buttery peanut flavor that makes this sheet cake so appealing.

Easy Peanut Butter Cake with Peanut Butter Frosting

A thin, tender peanut butter Texas sheet cake baked in a jelly-roll pan and covered with warm, creamy peanut butter frosting. It makes about 24 servings and is ready in approximately 45–55 minutes.

Print Recipe Pin Recipe

Prep Time 20 minutes mins

Cook Time 18 minutes mins

Total Time 45 minutes mins

Servings: 24 servings

Ingredients Method Notes

Ingredients

  

Cake

• 2 cups (240 g) All-purpose flour
• 2 cups (400 g) Granulated sugar
• 1 teaspoon Baking soda
• 1/2 teaspoon Salt
• 1 cup (227 g) Unsalted butter
• 1 cup Water
• 1/2 cup Creamy peanut butter
• 2 eggs Large eggs
• 1/2 cup Buttermilk
• 1 teaspoon Vanilla extract

Peanut Butter Frosting

• 1/2 cup (113 g) Unsalted butter
• 1/2 cup Creamy peanut butter
• 6 tablespoons, plus more if needed Milk
• 1 teaspoon Vanilla extract
• 4 cups (about 480 g) Powdered sugar, sifted

Method

 

Step-by-Step

1. Heat the oven to 375°F (190°C). Grease and lightly flour a 15 x 10-inch jelly-roll pan.
2. Whisk the flour, granulated sugar, baking soda, and salt together in a large bowl.
3. Combine the butter, water, and peanut butter in a saucepan over medium heat. Heat until melted and smooth, but do not let the mixture boil vigorously.
4. Pour the warm peanut butter mixture into the dry ingredients and stir until mostly combined.
5. Whisk the eggs, buttermilk, and vanilla together in a separate bowl. Add this mixture to the batter and stir only until smooth.
6. Spread the batter evenly in the prepared pan. Bake for 18–22 minutes, until the center springs back lightly and a toothpick comes out with only a few moist crumbs.
7. For the frosting, heat the butter, peanut butter, and milk in a saucepan until melted and smooth. Remove the pan from the heat and stir in the vanilla.
8. Gradually beat or whisk in the sifted powdered sugar until the frosting is smooth and spreadable. Add a teaspoon or two of milk if it feels too thick.
9. Spread the frosting over the cake while it is still warm. Let the cake cool before slicing into squares.

Notes

Use regular creamy peanut butter rather than natural peanut butter for the most consistent batter and frosting. Do not overbake the thin cake, and frost it while warm so the topping spreads easily and sets into a smooth, slightly fudgy layer.

Final Thoughts

This easy peanut butter cake with peanut butter frosting is the kind of dependable dessert that earns a permanent place in a home baker’s recipe collection. The ingredients are familiar, the method is straightforward, and the warm frosting gives the finished cake a wonderfully soft, creamy top.

Remember the three keys to success: use regular creamy peanut butter, avoid overbaking, and frost the cake while it is warm. Once cooled and sliced, these tender peanut butter squares are ready to share with family, friends, or anyone who appreciates a classic homemade dessert.