Easy Mississippi Mud Cookies with a Cake Mix
Updated Jan 23, 2026, Published Jul 21, 2020
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You already know that I am a huge fan of cookies! Make that a chocolate cake mix cookie that is covered in more chocolate and well, it doesn’t get any better than that. Unless of course, you add mini marshmallows. These Mississippi Mud Cookies cover all of the above. Yum!
Normally I am not a marshmallow fan when you eat them alone. But put them in the middle of chocolate and you have my full attention. That’s why I love these Fudgy Rocky Road Cookies so much!
Mississippi Mud Cake is said to be named because of the dense cake that looks like the banks of the Mississippi River.
They say that it is actually better on the 3rd day after baking because the flavors have time to develop. These cookies are great that way too. They stay fresh for a long time.
How to Make Mississippi Mud Cookies with a Cake Mix
Begin by combining the cake mix, eggs and oil. Remember to whisk the dry cake mix before adding the other ingredients. This will eliminate any lumps in the mix in this recipe and my other chocolate cake mix cookie recipes.
This can be done by hand but a hand mixer makes the job super simple. The dough will be thick and slightly sticky.
Scoop mounds of dough onto a silicone mat {or parchment} lined baking sheet. A medium cookie scoop works well and keeps all of the cookies the same size.
Bake in a 350 degree oven for 8 minutes and then remove from the oven. Use the back of the cookie scoop {or your thumb} to create an indention in the middle of each cookie.
Because this is a Mississippi Mud Cake we will be using mini marshmallows. If you don’t have them, cut larger marshmallows into quarters.
Place four mini marshmallows into the indention of each cookie. Return to the oven for an additional 3-4 minutes or until the marshmallows puff up and melt.
Remove from the oven again and let the cookies cool completely on the cookie sheet before moving them to a cooling rack.
How to make Cooked Frosting For Mississippi Mud Cookies
While the cookies are cooling, turn your attention to the cooked frosting.
In a sauce pan over medium-high heat begin melting butter.
Once the butter is melted, add the milk and cocoa to the butter and whisk well.
Cook for 2-3 minutes, stirring constantly, until the mixture is slightly thickened.
Remove from the heat and add the vanilla extract and powdered sugar. Whisk until smooth.
You can even use a hand held mixer to combine the ingredients if you want to.
Once the mixture is smooth, spoon a large teaspoon of frosting over the top of each cookie. It should cover the marshmallows.
You can let the cookies set up at room temperature or refrigerate them for about 30 minutes if you want to speed up the process.
5 Tips for making Mississippi Mud Cookies Perfectly with a Cake Mix
- Whisk the dry cake mix before adding the wet ingredients. This will take out any of lumps in the dry mix because are almost impossible to remove once the oil and eggs are mixed in.
- Don’t over bake the cookies. Bake for 8 minutes before making the indention in the middle because you want them to cook long enough that they aren’t totally doughy. Add the marshmallows and then only bake them long enough to melt the marshmallows. Over baking cake mix cookies will cause them to be super dry.
- Let the cookies cool completely before adding the cooked frosting. If you add the frosting to hot cookies it will not set up nicely.
- When making the frosting be sure that you remove the mixture from the heat before adding the vanilla and powdered sugar. If you add the vanilla over the heat it can evaporate and eliminate the flavor.
- Let the frosting set up completely before stacking the cookies. Otherwise they will stick together and you end up with one super large stacked cookie.
The result is a super delicious and extra moist Mississippi Mud cookie that is made even more special with the addition of melted marshmallows.
They are the perfect cookie for any season. I can’t wait to add these to my Christmas Cookie baking list this year along with Pomegranate Cookies and Hot Cocoa Peppermint Cookies!
Do you love frosted cookies? Try these recipes…
- Easy Strawberry Cake Mix Cookies
- Peanut Butter Texas Sheet Cake Cookies
- Texas Sheet Cake Cookies
- Lemon Poppy Seed Sheet Cake Cookies
- Toffee Sheet Cake Cookies
- Celebration Sheet Cake Cookies
Easy Mississippi Mud Cookies with a Cake Mix
Ingredients
Chocolate Cookies
- 1 box chocolate cake mix, {13.25 ounces}
- ¼ cup all purpose flour
- 2 large eggs
- 1/3 cup vegetable oil
- ½ cup chopped pecans
- 64 mini marshmallows
Chocolate Cooked Frosting
- ¼ cup butter
- 1 Tablespoon unsweetened cocoa powder
- 1 ½ Tablespoons milk, {I used 2%}
- 1-1¼ cups powdered sugar
Instructions
- Preheat the oven to 350°.
- Combine the cake mix and flour in a large bowl and whisk to combine. Add the eggs and oil to the dry ingredients and mix using an electric mixer until ingredients are completely incorporated. Add the chopped pecans and stir into the cookie dough until they are evenly distributed.
- Using a medium sized cookie scoop {or heaping tablespoon}, scoop cookies onto a silicone {or parchment} lined cookie sheet.
- Bake for 7 minutes and remove cookies from oven. Remove from the oven and press 4 mini marshmallows into the top of each cookie. Return cookies to the oven for an additional 2-3 minutes or until the marshmallows have puffed and melted. Remove from oven and let the cookies cool completely on the cookie sheet.
Chocolate Frosting
- While the cookies are cooling begin making the cooked frosting. Combine the butter, cocoa and milk in a medium sauce pan over medium heat. Cook and whisk until the ingredients are melted and mixed together and that any lumps are gone. Remove from heat and add the powdered sugar. Whisk until combined and smooth.
- Spoon a heaping teaspoon of frosting over the top of each cookie, being sure to cover the marshmallows. Let the cookies sit at room temperature until the frosting is set up. Refrigerate for 30 minutes if you want to speed up the process.
Notes
Nutrition
Nutrition information is automatically calculated, so should only be used as an approximation.
The chocolate lovers in my family were obsessed with these cookies!