Mississippi Mud Cupcakes (Fudgy Chocolate Cupcakes with Marshmallow and Fudge Frosting)
These Mississippi Mud Cupcakes are rich, fudgy, and packed with deep chocolate flavor, topped with gooey marshmallows and a glossy fudge frosting. With a soft, slightly dense crumb and that signature “mud” texture, these bakery-style cupcakes are perfect for chocolate lovers.
Servings 12 cupcakes
Calories 400kcal
Cost $10 for entire recipe
Equipment
- 12-cup muffin pan – for evenly sized cupcakes
- Cupcake liners – prevents sticking and makes cleanup easy
- Mixing bowls (2–3) – for separating wet and dry ingredients
- Whisk – for smooth batter and cocoa blooming
- Rubber spatula – for folding and scraping batter
- Measuring cups and spoons – for accurate ingredient portions
- Kitchen scale (optional but recommended) – for precise baking measurements
- Saucepan – to prepare the fudge frosting
- Cooling rack – allows cupcakes to cool evenly
- Spoon or offset spatula – for spreading the frosting smoothly
Ingredients
Chocolate Cupcakes
- ¾ cup 92g all-purpose flour
- ½ cup 50g cocoa powder (natural or Dutch-process)
- ¾ tsp baking soda
- ⅛ tsp baking powder
- ½ tsp salt
- ¾ cup 150g granulated sugar
- ½ cup 100g brown sugar
- ⅓ cup 80ml / ~70g vegetable oil
- 2 tbsp 28g melted butter
- ¼ cup 60g sour cream
- 2 large eggs room temperature
- 1 tsp vanilla extract
- ½ cup 120ml buttermilk (room temperature)
- ⅓ cup + 1 tbsp 95ml hot coffee
Marshmallow Layer
- 1½ cups mini marshmallows 75–85g
Fudge Frosting
- ½ cup 115g unsalted butter
- ¼ cup 60ml milk
- ¼ cup 25g cocoa powder
- 2¼ cups 270g powdered sugar, sifted
- 1 tsp vanilla extract
- Pinch of salt
- 1 tbsp corn syrup optional, for gloss
Instructions
Prepare
- Preheat oven to 350°F (175°C). Line a 12-cup muffin pan with cupcake liners.
Bloom Cocoa
- In a bowl, whisk together cocoa powder and hot coffee until smooth.
- Whisk in buttermilk and sour cream until fully combined.
Make Batter
- In a separate bowl, whisk sugars, oil, melted butter, eggs, and vanilla until smooth.
- Mix in the cocoa mixture.
- Add flour, baking soda, baking powder, and salt.
- Fold until just combined—do not overmix.
Bake
- Divide batter evenly (about ¼ cup per liner, ¾ full).
- Bake for 16–19 minutes, or until a toothpick inserted shows moist crumbs.
- Let cupcakes cool for 2 minutes.
Add Marshmallows
- Top each cupcake with mini marshmallows and gently press.
- Return to oven for 1–2 minutes, until marshmallows are puffed (not melted flat).
- Cool cupcakes for 10–15 minutes.
Make Fudge Frosting
- In a saucepan over medium heat, melt butter.
- Whisk in milk and cocoa powder until smooth. Remove from heat and let cool for 2 minutes.
- Stir in vanilla and corn syrup (if using).
- Gradually whisk in powdered sugar until smooth and glossy.
Assemble
- Spoon frosting over marshmallows and gently spread.
- Serve slightly warm or at room temperature.
Notes
- Do not overbake the cupcakes – removing them when a toothpick shows moist crumbs ensures the soft, fudgy “Mississippi mud” texture instead of a dry, cakey result.
- Blooming the cocoa powder with hot coffee enhances the deep chocolate flavor without making the cupcakes taste like coffee. This step is key for rich chocolate cupcakes.
- Use room temperature ingredients (eggs, buttermilk, sour cream) for a smoother batter and more even baking.
- Mix just until combined once the flour is added. Overmixing can make the cupcakes dense and tough instead of soft and tender.
- Mini marshmallows should be lightly melted, not fully dissolved—only heat until they puff to keep that classic gooey layer.
- Fudge frosting texture matters: it should be thick, glossy, and spreadable. If it becomes too thick, add a small splash of warm milk; if too thin, let it sit for a few minutes to thicken.
- Corn syrup is optional but helps create a shiny, soft frosting that stays smooth longer—great for presentation and photos.
- Natural cocoa powder gives slightly better rise, but Dutch-process cocoa works well for a smoother, milder chocolate flavor.
- For a traditional Mississippi Mud finish, sprinkle chopped pecans or walnuts over the frosting after spreading.
- These cupcakes taste best slightly warm or at room temperature, when the marshmallow layer is soft and the frosting is perfectly fudgy.