My niece is officially the first person to be featured on the Herby Eater. I am even featuring her hand in the photo above, a photo I took as I was trying to capture the full cake she helped make, but she couldn’t quite wait to pick off some of the peanuts she had decorated with. It’s a deeply moist chocolate layer cake, made the old-fashioned “boiling water” way, which is the trick behind the most tender chocolate cakes that I learned long ago. It’s filled and covered in a whipped peanut butter frosting, then finished with a ring of almonds and a pile of chopped roasted peanuts right in the center. Decorated and made by me and my 7 year old niece, who did a lot of the work alongside the KitchenAid! So consider this her recipe, through me.
You may think this came from an, albeit slightly slopping, bakery case. It didn’t. It came from my nieces brain after watching an “Is It Cake?” recipe, my brain for knowing cake ratios, a stand mixer, and about an hour or two of your afternoon.
Why This Chocolate Peanut Butter Cake Works! (AS I am sure you assume, because… duh)
The boiling water method. Pouring boiling water into chocolate cake batter feels innately wrong the first time you do it. The batter goes thin, almost soupy, and you’ll wonder if you made a serious mistake. You didn’t. The hot water blooms the cocoa powder, deepening the chocolate flavor and keeping the crumb ultra-moist; no dry chocolate cake here!
Whipped, not just beaten, frosting. Folding whipped cream into a peanut butter buttercream base lightens it up considerably. Standard peanut butter frosting can turn heavy and almost fudgy in large amounts; whipping in cream keeps it spreadable and gives it a little lift, which matters when you’re frosting and filling a full two-layer cake.
The nut topping is doing more than decorating. The ring of almonds was the brain child of my niece but it isn’t just there to look nice on Instagram (though it does that too); it actually gives you a clean border to fill in, and the contrast between the smooth almonds around the edge and the roughly chopped peanuts in the center adds textural variety to every slice. A smart move on her part!
Ingredient Notes
- Cocoa powder: A natural unsweetened cocoa works well here and is what gives this cake its deep flavor without leaning bitter.
- Heavy cream: Make sure it’s cold before whipping; it’ll hold its structure better once folded into the peanut butter mixture.
- Almonds and peanuts: Raw or lightly toasted almonds for the border, roasted and salted peanuts (chopped) for the center; the salt on the peanuts plays nicely against the sweetness of the frosting.
Tips for Success
- Measure your dry ingredients before you start heating the water for the batter. Once that water boils, you want to move quickly!
- Let the cake layers cool completely before frosting. This is SUPER KEY. A warm cake will melt the frosting right off the sides.
- If your kitchen runs warm, chill the frosted cake for 15–20 minutes before slicing for cleaner cuts.
- Doing a thin crumb coat first, then chilling briefly before the final frosting layer, will give you smoother sides if you want a more polished look.
Storage
This cake keeps well covered at room temperature for up to two days. For longer storage, refrigerate it for up to five days, but let slices come back to room temperature before serving — cold butter and peanut butter frosting can taste dull and firm straight from the fridge.
[Get the full printable recipe card, with exact measurements and step-by-step instructions, below.]
Frequently Asked Questions
Can I make this cake ahead of time? Yes. Bake the cake layers up to a day in advance, wrap them tightly once fully cooled, and store at room temperature. Frost the next day.
Can I use natural peanut butter instead of regular? You can, but expect a softer, oilier frosting. If using natural peanut butter, stir it very well and consider reducing the cream slightly to compensate.
Why did my batter turn out so thin? That’s normal for this method. The boiling water is meant to thin the batter significantly — it bakes up into a dense, moist cake despite the runny appearance going into the oven.
Can I make this into cupcakes instead of a layer cake? Yes — this batter converts well to cupcakes. Fill liners about two-thirds full and start checking for doneness around 18–20 minutes.
Elizabeth’s Special Chocolate Cake with Peanut Butter Frosting
Equipment
- Two 9-inch round cake pans
- Mixing bowls (one large, one medium)
- Stand mixer or hand mixer
- Whisk
- Rubber spatula
- Wire cooling rack
- Offset spatula (for frosting)
- Cake stand or serving plate
- Toothpick (for doneness check!)
Ingredients
For the Chocolate Cake
- 2 cups 400g granulated sugar
- 1 3/4 cups 220g all-purpose flour
- 3/4 cup 65g unsweetened cocoa powder
- 1 1/2 tsp baking soda
- 1 1/2 tsp baking powder
- 1 tsp salt
- 2 large eggs
- 1 cup 240ml whole milk
- 1/2 cup 120ml vegetable oil
- 2 tsp vanilla extract
- 1 cup 240ml boiling water
For the Whipped Peanut Butter Frosting
- 1 cup 2 sticks / 226g unsalted butter, softened
- 1 1/2 cups 390g creamy peanut butter
- 4 cups 480g powdered sugar, sifted
- 1/2 cup 120ml heavy whipping cream, whipped to soft peaks
- 1 tsp vanilla extract
- Pinch of salt to taste
For the Topping
- 1/2 cup 70g whole almonds
- 1/2 cup 70g roasted peanuts, roughly chopped
Instructions
For The Cake:
- Preheat the oven to 350°F (175°C). Grease and flour two 9-inch round cake pans, or line the bottoms with parchment.
- In a large bowl, whisk together the sugar, flour, cocoa powder, baking soda, baking powder, and salt.
- Add the eggs, milk, oil, and vanilla. Beat on medium speed for about 2 minutes, until smooth.
- Reduce the mixer to low and carefully stir in the boiling water. The batter will be very thin — that’s expected.
- Divide the batter evenly between the prepared pans.
- Bake for 28–32 minutes, or until a toothpick inserted in the center comes out clean.
- Cool the cakes in the pans for 10 minutes, then turn out onto a wire rack to cool completely before frosting.
Make The Frosting:
- Beat the softened butter and peanut butter together until smooth and creamy, about 2 minutes.
- Add the powdered sugar in two additions, beating well after each.
- In a separate bowl, whip the heavy cream to soft peaks.
- Gently fold the whipped cream and vanilla into the peanut butter mixture until light and fluffy. Add a pinch of salt to taste.
Assemble:
- Place one cake layer on a serving plate or cake stand. Spread a layer of frosting evenly on top.
- Add the second cake layer and frost the top and sides of the cake with the remaining frosting.
- Arrange the whole almonds in a ring around the border of the top of the cake.
- Fill the center with the chopped roasted peanuts.
- Slice and serve.
Notes
Frosting amount is generous enough for filling, crumb coat, and full frosting; if you prefer a thinner coat, you may have a little frosting left over.
Cake layers can be baked a day ahead! Wrap tightly in plastic wrap once fully cooled and store at room temperature.
Store the finished cake covered at room temperature for up to 2 days, or refrigerated for up to 5 days (bring to room temp before serving for the best texture).