Introduction

Mississippi Mud Cake is a rich, fudgy chocolate dessert topped with gooey marshmallows and a creamy cocoa frosting. Its moist texture and indulgent flavors make it a favorite for chocolate lovers looking for a decadent homemade treat.

A square white dish holds a rich chocolate brownie layer at the bottom, dark and dense with a moist texture. Above it is a lighter, creamy layer mixed unevenly with the chocolate, showing swirls of white and brown creating a marbled effect. The top layer is glossy and cracked chocolate, covering all squares except one missing piece near the front. To the back right, a small white bowl filled with mixed nuts sits on a white marbled surface, adding a rustic touch to the scene. photo taken with an iphone --ar 4:5 --v 7

Ingredients

2 cups (240g) all-purpose flour
2 cups (400g) granulated sugar
½ cup (50g) unsweetened cocoa powder
2 teaspoons (9-10g) baking powder
1½ teaspoons (7-8g) baking soda
½ teaspoon (2-3g) salt
½ cup (120ml) oil (vegetable or canola)
2 eggs (room temperature)
1 teaspoon (5ml) vanilla extract
½ cup (120ml) whole milk
¼ cup (60g) sour cream
1 cup (237ml) boiling water
10 ounces (284g) mini marshmallows
½ cup (112g) salted butter (softened)
6 tablespoons (90g) heavy cream
3 tablespoons (18g) cocoa powder
1 teaspoon (5ml) vanilla extract
2-3 cups (240-360g) powdered sugar
Walnuts for garnish (optional)

Instructions

Step 1: Preheat your oven to 350℉ (175℃) and lightly grease a 9×13-inch baking pan.
Step 2: In a medium bowl, sift together the flour, sugar, cocoa powder, baking powder, baking soda, and salt. Set aside.
Step 3: In a large bowl, use an electric mixer to combine the oil, eggs, vanilla extract, milk, and sour cream until well mixed, taking care not to overmix.
Step 4: Slowly add the boiling water on low speed, then beat on high for one minute to aerate the batter.
Step 5: Gradually add the dry ingredients to the wet ingredients and mix until just combined.
Step 6: Pour the batter into the prepared pan and bake for 30 minutes. Test doneness with a toothpick; it should come out clean.
Step 7: Remove the cake from the oven, spread mini marshmallows evenly over the top, and return to the oven for 2 minutes until marshmallows soften slightly. Let the cake cool completely.
Step 8: For the frosting, melt the softened butter in a small saucepan. Stir in heavy cream and cocoa powder, cooking and stirring for about 2 minutes.
Step 9: Remove from heat and mix in the vanilla extract. Using an electric mixer, gradually beat in the powdered sugar until the frosting is smooth.
Step 10: Immediately drizzle the frosting over the cooled cake. Refrigerate for 25-30 minutes to allow the frosting to set before serving.

Tips & Variations

Use room temperature eggs for better batter mixing and rise.
For extra texture, sprinkle chopped walnuts on top when adding marshmallows.
Substitute sour cream with Greek yogurt for a slightly tangier flavor.
Add a pinch of espresso powder to the batter to intensify the chocolate flavor.
If mini marshmallows aren’t available, regular marshmallows cut into smaller pieces work well.

Storage

Store the Mississippi Mud Cake covered in the refrigerator for up to 4 days. Bring it to room temperature or warm slices briefly in the microwave before serving to soften the frosting. This cake can also be frozen for up to 2 months; thaw in the refrigerator overnight for best results.

How to Serve

A close-up view of two square brownie pieces on a white plate, each with three layers: a dark, moist chocolate cake base, a middle layer of white marshmallow, and a top smooth caramel layer with a shiny, slightly cracked surface. Scattered on top are walnut and pecan halves adding texture. One piece has a bite taken out, showing the contrast of layers, with a silver fork resting on the plate nearby. The background is a white marbled texture. photo taken with an iphone --ar 4:5 --v 7

Serve this delicious recipe with your favorite sides.

FAQs

Can I make this cake gluten-free?

Yes, substitute the all-purpose flour with a gluten-free flour blend that includes xanthan gum to maintain the cake’s texture.

Why is the boiling water added to the batter?

Adding boiling water helps dissolve the cocoa powder fully and creates a thinner batter that results in a moist, tender cake crumb.