Dessert

Ultimate Mississippi Mud Brownies that Melt in Your Mouth Recipe

ByElla Hart February 18, 2026February 18, 2026

Introduction

If you’re craving rich, fudgy brownies with a gooey marshmallow twist, these Ultimate Mississippi Mud Brownies are exactly what you need. They melt in your mouth and feature a luscious chocolate frosting that perfectly complements the soft, decadent texture. Perfect for any occasion, these brownies are sure to impress.

A rich, three-layer chocolate dessert slice sits on a wooden board with a white marbled texture background. The bottom layer is a dense, dark chocolate cake with a moist and crumbly texture. Above this is a thick, smooth milk chocolate mousse layer, which looks creamy and soft. The top layer is a thick, fluffy white cream topped with numerous curled dark chocolate shavings that are shiny and slightly curved. A small drop of glossy chocolate sauce is seen on the wooden board near the dessert. Photo taken with an iphone --ar 4:5 --v 7

Ingredients

1 cup unsweetened cocoa powder
1/2 cup oil
1/2 cup butter, softened (unsalted recommended)
1 cup granulated sugar
4 large eggs
1 teaspoon vanilla extract
1 cup all-purpose flour
1/2 teaspoon salt
2 cups mini marshmallows
1/2 cup melted butter (for frosting)
1/4 cup unsweetened cocoa powder (for frosting)
1/4 cup evaporated milk
1 teaspoon vanilla extract (for frosting)
3 cups powdered sugar

Instructions

Step 1: Preheat your oven to 350°F and grease a 9×13” pan with non-stick cooking spray.
Step 2: In a large mixing bowl, whisk together the oil and 1 cup of cocoa powder until smooth.
Step 3: Add the softened butter and blend until creamy, then mix in the granulated sugar.
Step 4: Add eggs one at a time, mixing after each addition, then stir in 1 teaspoon vanilla extract.
Step 5: Gently mix in the flour and salt, taking care not to overmix the batter.
Step 6: Pour the batter into the prepared pan and bake for 25-30 minutes.
Step 7: Remove from oven, sprinkle mini marshmallows evenly on top, and return to the oven for an additional 2-3 minutes until marshmallows are soft and slightly melted.
Step 8: Let the brownies cool completely in the pan.
Step 9: To make the frosting, mix melted butter, 1/4 cup cocoa powder, evaporated milk, and 2 cups powdered sugar in a bowl until smooth.
Step 10: Gradually add the remaining powdered sugar until you reach your desired frosting consistency.
Step 11: Spread the frosting evenly over the cooled brownies, cut into squares, and serve.

Tips & Variations

For an extra fudgy texture, substitute half of the all-purpose flour with almond flour.
You can swap mini marshmallows for chopped nuts if you prefer a crunchy topping.
Use dark cocoa powder for a more intense chocolate flavor.
If frosting is too thick, add a splash of milk to loosen it up.

Storage

Store brownies in an airtight container at room temperature for up to 3 days. For longer storage, keep them in the refrigerator for up to a week. Reheat individual pieces gently in the microwave for 10-15 seconds to soften the marshmallow layer before serving.

How to Serve

A close-up of a rich, three-layer chocolate dessert square on a wooden board with a white marbled texture in the background. The bottom layer is dark, dense, and moist chocolate cake. The middle layer is a slightly lighter, creamy chocolate mousse with a smooth texture. The top layer is thick, white whipped cream, generously topped with dark chocolate curls scattered across the surface. A glossy chocolate drizzle is near the base of the cake slice, adding shine and extra richness. Photo taken with an iphone --ar 4:5 --v 7

Serve this delicious recipe with your favorite sides.

FAQs

Can I use regular marshmallows instead of mini marshmallows?

Yes, but cut regular marshmallows into smaller pieces so they melt evenly and cover the top layer well.

Can these brownies be frozen?

Absolutely! Wrap the cooled, unfrosted brownies tightly in plastic wrap and foil, then freeze for up to 3 months. Thaw overnight in the fridge and frost before serving.