3 Musketeer Mississippi Mud Cake

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3 Musketeer Mississippi Mud Cake a rich, dense brownie is topped with toasted marshmallows, 3 Musketeers candy bars and chocolate ganache.

3 Musketeer Mississippi Mud Cake will make your head explode. It’s chocolate heaven for the chocoholics.

3 Musketeers Mississippi Mud Cake

I’ll just be honest I have two plastic containers and a drawer full of chocolate at all times. I really hate to run out of an ingredient when I’m cooking so I tend to have too much of everything all the time. And, I pick up chocolate for baking after holidays when it’s on sale whether I need it or not… because #onsale. I went a little overboard after Christmas this year. That’s when in addition to the plastic containers,  I had to start using a deep drawer to hold it all. I told my boys, this chocolate is not snacking chocolate. This chocolate is blog chocolate. Lincoln said, “What’s blog chocolate?” “It’s for the blog.” “But, it’s just chocolate, Mom.” “No, it’s in the drawer, it’s for the blog.” At which point, he took my hand, looked me in the eye and said, “Mom, you do know that chocolate is the same as the other chocolate, right?”

Mississippi mud cake with pieces of 3 Musketeers inside.

Whatever. At least they don’t snack on the blog chocolate and I have it to make outrageously decadent desserts like 3 Musketeer Mississippi Mud Cake for you!

I’ve made Mississippi Mud Cake (some people call it Rocky Road Brownies) a lot of times, but never 3 Musketeer Mississippi Mud Cake. In fact, along with Strawberry Cake, it was my favorite dessert growing up. Why didn’t I think to add another chocolate layer to my favorite kicked up brownies before now?!

3 Musketeer MS Mud Cake

3 Musketeers Mississippi Mud Cake Tips

  • I use semi-sweet chocolate baking bars for this dessert. I like it better than using chocolate chips. Without getting into the geeky side of chocolate, I’ll just say the bars melt smoother than chips and leave it at that. I find the chocolate baking bars on the baking isle where they stock chocolate chips and cocoa powder. You can read my tips on How to Melt Chocolate for the best results.
  • I also like small marshmallows versus the large ones. The big marshmallows, well, they’re just too big. Get the plain minis, not the flavored ones.
  • You’ll want the butter and eggs to be at room temperature. Just sit them on the counter for an hour and you’ll be good to go.
  • Lastly, don’t over-beat this mixture. If you’re using an electric mixer, stir on low until everything is combined and smooth about 1 minute. If you’re using muscle power and stirring it by hand (I respect you), mix until everything is combined and smooth and you don’t see dry flour or cocoa.
3 Musketeer Mississippi Mud Cake 3

3 Musketeer Mississippi Mud Cake

Fudgy brownies are topped with chocolate frosting and 3 Musketeer Bars.
Author: Paula
5 from 1 vote
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Prep Time: 15 minutes
Cook Time: 40 minutes
Total Time: 55 minutes
Servings: 16 slices



Chocolate Frosting


  • Preheat oven to 350 degrees.
  • Line a 15x10x1 inch sheet pan with foil or parchment paper. Spray with non-stick spray.
  • Microwave 1 cup butter and chocolate in a microwave-safe bowl at 30 second intervals until melted. Stir to combine and allow to cool.
  • Combine sugar, flour, cocoa and salt.
  • Combine eggs and vanilla with cooled chocolate.
  • Add egg mixture to flour mixture and mix until combined and smooth.
  • Pour onto prepared sheet pan.
  • Bake at 350 degrees for 20 minutes.
  • Carefully remove from oven and spread marshmallows evenly over brownie layer.
  • Return to oven and bake 8 to 10 minutes to toast marshmallows.
  • Remove from oven and immediately sprinkle with 3 Musketeer candy bars.

Make Chocolate Frosting:

  • Combine butter, cocoa and milk in a small sauce pan over low heat. Cook 2 to 3 minutes until butter is melted and mixture thickens slightly.
  • Add confectioners sugar one cup at a time, whisking to combine.
  • Add vanilla and whisk until smooth.
  • Pour over slightly cooled cake.


Calories: 546kcal | Carbohydrates: 86g | Protein: 5g | Fat: 22g | Saturated Fat: 14g | Cholesterol: 99mg | Sodium: 301mg | Potassium: 153mg | Fiber: 2g | Sugar: 68g | Vitamin A: 620IU | Calcium: 31mg | Iron: 2mg
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  1. Do you think it would turn out ok in a 9×13 pan if I cook a little longer?
    Jan Hulsey

  2. This 3 musketeer Mississippi mud cake definitely made my head explode. It just looks so amazing. The soft texture of the brownie and the wonderful chocolate ganache. It really is something to love!

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Your email address will not be published. Have you tried this recipe? Consider giving it 5 stars!