Every year when my birthday rolls around, I have the same thought:
“It’s August. It’s hot. Why am I even pretending a regular cake is an option?”
Growing up, I was that kid who always asked for ice cream cake. Not because it was trendy — but because who wants to blow out candles over something that’s already melting? Back then it was usually a mint chocolate chip situation (which no one else in my family liked — their loss, my gain).
But a few years ago, I had a new idea: what if I built a cake around one of my favorite sandwiches ever — the fluffernutter? Peanut butter + marshmallow fluff = pure comfort. And if you swap bread for peanut butter cake, add a thick layer of homemade peanut butter ice cream, and top it all off with marshmallow frosting… well, suddenly you’ve got a birthday dessert worth bragging about.
This isn’t the kind of thing you make on a whim. It’s not hard, but it does require a little planning — the cake needs to cool, the ice cream needs to churn and freeze, and the frosting comes together best when you’re not in a rush. But the end result is everything: creamy, sweet, a little salty, and the perfect mix of frozen and fluffy.
If you’ve got a birthday coming up (or you just want to make Tuesday feel special), this is your cake.
What You’ll Need
Peanut Butter Cake
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¾ cup gluten-free flour blend (or regular AP flour if you don’t need gluten-free)
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1 tsp baking powder
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¼ tsp baking soda
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¼ tsp salt
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2 ½ Tbsp canola oil
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2 ½ Tbsp smooth peanut butter
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½ cup dark brown sugar, packed
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1 large egg
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1 cup buttermilk
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½ tsp vanilla extract
Peanut Butter Ice Cream
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2 cups heavy cream
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1 cup 1% or 2% milk
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1 tsp salt
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3 egg yolks
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1 cup sugar
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½ cup smooth peanut butter
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½ tsp vanilla extract
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⅔ cup marshmallow fluff (for the middle layer)
Marshmallow Frosting
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6 egg whites
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1 ⅓ cups sugar
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4 sticks unsalted butter, softened and cut into tablespoons
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1 tsp vanilla extract
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⅔ cup marshmallow fluff
| Prep Time | Chill Time | Total Time | Servings | Difficulty |
|---|---|---|---|---|
| 20 minutes | 4–6 hours | about 6 hours 20 minutes | 8–10 slices | Easy |
How to Make It
Step 1: Bake the Cake
Heat oven to 350°F. Line a 9-inch round pan with parchment, grease lightly. Whisk flour, baking powder, baking soda, and salt. In another bowl, beat oil, peanut butter, and sugar until fluffy. Mix in egg. Alternate adding buttermilk and dry ingredients in two batches, ending with dry. Stir in vanilla. Bake 30 minutes or until a toothpick comes out clean. Cool completely.
Step 2: Make the Ice Cream
Set up an ice bath with a large bowl of ice water and a smaller bowl with a strainer on top. Heat cream, milk, and salt until steaming. In another bowl, whisk yolks, sugar, peanut butter, and vanilla. Slowly whisk in half the hot cream to temper. Return everything to the pot and cook a few minutes until slightly thickened. Strain into the prepared bowl. Cool, then refrigerate 3 hours or overnight. Churn until thick and creamy.
Step 3: Make the Frosting
Over simmering water, whisk egg whites and sugar until sugar dissolves. Transfer to a stand mixer, beat until stiff peaks form. Add butter one tablespoon at a time, beating well after each addition. Mix in vanilla, then marshmallow fluff.
Step 4: Assemble
Line a springform pan with parchment. Place the cake in the bottom. Spread marshmallow fluff on top. Add churned ice cream, smooth it out, and freeze overnight. Frost with marshmallow frosting right before serving, or freeze again for a firmer texture.
A Few Pro Moves
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Want crunch? Sprinkle chopped peanuts or crushed peanut butter cookies between the fluff and ice cream.
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Chocolate fan? Drizzle a thin layer of ganache over the marshmallow layer before adding the ice cream.
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Hate making frosting? Skip it and top the cake with whipped cream right before serving.
If you serve this at a summer party, don’t expect leftovers. Someone will be standing at the freezer with a fork before you even get the plates out.
FAQ
Can I make this without an ice cream maker?
Yes. Freeze the ice cream base in a shallow dish, stirring every 30–45 minutes until creamy, or use a no-churn recipe with whipped cream and sweetened condensed milk blended with peanut butter.
Can I use store-bought ice cream?
Absolutely. Just soften it slightly before spreading over the marshmallow layer. Peanut butter cup or vanilla both work great.
How far ahead can I make this?
You can assemble the cake (without frosting) up to 3 days ahead and keep it tightly wrapped in the freezer. Frost the day you plan to serve.
Can I skip the marshmallow frosting?
Yes. You could frost with whipped cream, buttercream, or even leave it bare and just dust with cocoa powder or powdered sugar before serving.
Is there a dairy-free version?
Swap the milk and cream for coconut cream and almond milk, use vegan butter in the cake and frosting, and choose a dairy-free ice cream base.
Jacklyn is a San Diego–based food journalist with a background in the confectionery world. Before diving into food reporting, she worked at a startup crafting plant-based, low-sugar sweets designed to make candy a little healthier
