Peanut Butter Marshmallow Cupcakes

These Peanut Butter Marshmallow Cupcakes are a simple, nostalgic treat: a moist peanut butter cupcake topped with pillowy marshmallow fluff that you can lightly toast for a caramelized finish. The flavor is rich and nutty, the texture balances tender cake with a soft, gooey top, and they’re worth making because they’re quick to assemble and crowd-pleasing.

They’re forgiving to bake and easy to adapt — use store-bought marshmallow fluff for a fast finish or toast mini marshmallows for extra texture. These cupcakes hold up well for a small gathering or a cozy afternoon snack.

Why This Peanut Butter Marshmallow Cupcakes Works

1. The peanut butter in the batter adds nutty depth and keeps the crumb moist.
2. Marshmallow fluff gives a pillowy, glossy topping that contrasts with the cake’s texture.
3. Uses pantry-friendly ingredients and straightforward mixing — no complicated techniques.
4. Easy to finish two ways: pipe and torch the fluff or top with mini marshmallows and broil briefly.

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Ingredients

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Here are the key ingredients and why each one matters.

– All-purpose flour: Provides structure; measure by spooning into the cup and leveling to avoid a dense cake.
– Peanut butter (creamy): The main flavor — creamy varieties blend best for a smooth batter.
– Sugar (granulated or partly brown): Granulated for lift, swap some brown sugar for deeper caramel notes.
– Eggs: Bind and add richness; room temperature eggs incorporate more easily.
– Butter or neutral oil: Butter adds flavor, oil keeps the crumb slightly more tender and moist.
– Milk or buttermilk: Adds moisture and tenderness; buttermilk gives a slightly tangy lift.
– Baking powder (and a pinch of baking soda if using brown sugar): Leavening to keep cupcakes light.
– Marshmallow fluff or mini marshmallows: Use fluff for smooth topping or mini marshmallows to toast on top.

Substitutions and Variations

– Swap peanut butter for sunflower seed butter to make them nut-free — expect a slightly different flavor and greener hue.
– Use all oil (vegetable or canola) instead of butter for a moister, slightly denser crumb.
– Replace milk with buttermilk for tang and lift; cupcakes may be a touch more tender.
– Fold in mini chocolate chips for a peanut butter–chocolate twist; they add pockets of melted chocolate.
– Use gluten-free 1:1 flour blend for a gluten-free version — texture can be a bit crumblier.
– Top with crushed roasted peanuts for crunch; it won’t change baking but adds contrast.

How to Make Peanut Butter Marshmallow Cupcakes

This is a summary — follow the full recipe card for exact amounts and bake times.

1. Preheat oven to 350°F (175°C) and line a 12-cup muffin tin with liners.
2. Whisk dry ingredients (flour, baking powder, salt) in a bowl.
3. Cream butter (or oil) with peanut butter and sugar until smooth, then beat in eggs one at a time and vanilla.
4. Alternate adding dry ingredients and milk to the peanut butter mixture, mixing until just combined.
5. Spoon batter into liners about two-thirds full and bake until a toothpick comes out with a few crumbs, about 18–22 minutes.
6. Cool cupcakes on a rack; once cool, top with marshmallow fluff or pipe it on.
7. Toast the fluff with a kitchen torch or place under a hot broiler 10–20 seconds to color lightly; garnish and serve.

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Tips for the Best Results

1. Measure flour correctly — spoon into the cup and level off to avoid dense cupcakes.
2. Use room-temperature eggs and butter so the batter emulsifies easily and bakes evenly.
3. Don’t overmix once you add the flour — stop as soon as it’s combined to keep the crumb tender.
4. If toasting under the broiler, watch closely—marshmallow browns in seconds.
5. Chill the frosting slightly if piping to get cleaner peaks and easier handling.

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Common Mistakes

– Overfilling cupcake liners, which leads to spillover — fix: fill to about two-thirds full.
– Overmixing after adding flour, causing tough cupcakes — fix: fold until just combined.
– Frosting warm cupcakes, which can make fluff slide off — fix: cool completely before topping.
– Burning the marshmallow under the broiler — fix: keep the oven door open and watch closely, or use a torch.
– Using natural, separated peanut butter without stirring, which affects texture — fix: stir natural peanut butter well and measure after blending.

Storage

Storing: Keep cupcakes in an airtight container at room temperature for up to 2 days. If your kitchen is warm, refrigerate to prevent the topping from getting sticky; refrigerated cupcakes last 3–4 days.

Freezing: You can freeze unfrosted cupcakes for up to 3 months—cool completely, wrap individually, and thaw before frosting. You can freeze fully assembled cupcakes, but marshmallow topping may change texture; best to freeze without the fluff if possible.

Reheating or serving later: Bring refrigerated cupcakes to room temperature before serving. If the marshmallow has firmed, briefly warm in a 300°F oven for 5–7 minutes or use a quick pass with a torch to soften and re-toast.

How to Serve Peanut Butter Marshmallow Cupcakes

– Serve with a glass of cold milk to balance the sweetness.
– Pair with strong coffee for an afternoon treat.
– Plate with a drizzle of melted chocolate or salted caramel for a dessert upgrade.
– Add a sprinkle of chopped roasted peanuts for texture.
– Serve warm for a gooey marshmallow experience, or chilled for firmer topping.

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More Helpful Notes

– If your peanut butter is oily, stir well and measure after blending to keep batter consistency.
– A small offset spatula makes spreading the marshmallow easier and neater.
– For even baking, rotate the pan halfway through if your oven has hot spots.
– If you want extra stability, fold a little powdered sugar into marshmallow fluff before piping.

Frequently Asked Questions

Peanut Butter Marshmallow Cupcakes

Pillowy vanilla cupcakes hide a gooey marshmallow center and wear a billowy peanut butter–marshmallow swirl crowned with salty crushed peanuts. A nostalgic bake that balances sweet, nutty, and fluffy in every bite.

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Prep Time: 30 minutes minutes

Cook Time: 18 minutes minutes

Total Time: 48 minutes minutes

Servings: 20

Ingredients

 

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Cupcakes

• ▢ 1 3/4 cups granulated sugar
• ▢ 1/2 cup vegetable oil
• ▢ 3 large eggs, at room temperature
• ▢ 2/3 cup plain Greek yogurt
• ▢ 2 teaspoons pure vanilla extract
• ▢ 2 1/4 cups all-purpose flour
• ▢ 2 3/4 teaspoons baking powder
• ▢ 3/4 teaspoon fine sea salt
• ▢ 1 cup milk, warmed
• ▢ 1 teaspoon apple cider vinegar stir into the warm milk

Filling

• ▢ 1 1/2 jars marshmallow creme (7-ounce jars)

Peanut Butter Swirl Frosting

• ▢ 1 1/4 cups unsalted butter, room temperature
• ▢ 3/4 cup creamy peanut butter
• ▢ 4 1/2 cups powdered sugar, sifted
• ▢ 3–4 tablespoons milk as needed for consistency
• ▢ 1 teaspoon pure vanilla extract
• ▢ 1 tablespoon honey
• ▢ 1/2 cup marshmallow creme for marbling the frosting

Finish

• ▢ 1 3/4 cups salted roasted peanuts, finely chopped
• ▢ pinch flaky sea salt (optional)

Instructions

Preparation Steps

• Heat the oven to 350°F. Line two standard muffin pans with 20 paper liners. Spread the peanuts on a sheet pan and toast for 5–6 minutes until fragrant, then cool and finely chop.
• Make the frosting first so it can set: In a stand mixer with the paddle, beat the butter on medium speed until creamy, about 2 minutes. Beat in the peanut butter for 1 minute until completely smooth.
• Add the powdered sugar in three additions, alternating with the milk and vanilla, mixing on low just until incorporated after each addition. Beat in the honey, then increase speed to medium-high and whip for 1–2 minutes until light. Fold in 1/2 cup marshmallow creme just until streaky to create a swirl. Transfer to a piping bag and refrigerate 20 minutes to firm slightly.
• For the cupcakes, whisk the flour, baking powder, and salt in a bowl. In a separate large bowl, whisk the sugar, oil, and eggs vigorously for 2–3 minutes until paler and slightly thick. Whisk in the yogurt and vanilla.
• Stir the vinegar into the warm milk. Add the dry ingredients to the egg mixture in two additions, alternating with the milk mixture, beginning and ending with dry. Fold just until the flour disappears, then let the batter rest 5 minutes to hydrate.
• Portion the batter into liners, filling each about 2/3 full. Bake 16–18 minutes, rotating pans halfway, until the tops spring back and a toothpick comes out with a few moist crumbs. Cool in the pan 5 minutes, then transfer to a rack to cool completely.
• Fill the cupcakes: Use a small paring knife to cut a 3/4-inch-wide, 1-inch-deep cone from the center of each cupcake. Spoon or pipe marshmallow creme into each cavity, then trim and replace the cake cap. Tip: Lightly oil your spoon or piping tip to keep marshmallow creme from sticking.
• Frost and finish: Pipe a tall swirl of the chilled peanut butter–marshmallow frosting on each cupcake. Roll the sides of the frosting in the chopped peanuts and finish with a tiny pinch of flaky salt, if using.

Notes

For the neatest peanut coating, keep the frosted cupcakes slightly chilled for 5–10 minutes before rolling in peanuts. Store covered at cool room temperature for 1 day or refrigerate up to 3 days; bring to room temp before serving for the softest crumb.

This recipe is an original creation inspired by classic Peanut Butter Marshmallow Cupcakes flavors. All ingredient ratios and instructions are independently developed.