This rocky road Texas sheet cake is a delightful twist on everyone’s favorite recipe. Chocolate cake topped with mini marshmallows that have been tossed in frosting then sprinkled with walnuts. This is one GIANT cake! This post contains affiliate links.
Watch our step by step video!
Texas sheet cake is just about the easiest cake to make for a crowd. 99% of the time I make my cakes using a boxed mix. I really can’t tell the difference when making a birthday cake, but that extra 1% is for Texas sheet cake. I have no problem whipping out one from scratch for the family on a weeknight. So fast, so easy (bakes up in 25 minutes!) and so forgiving. I love that you frost it while it’s warm for the smoothest, melt in your mouth, frosting.
Years ago I saw a chocolate marshmallow cake that I knew would be fantastic in sheet cake form. Dana shared how her mom used to toss marshmallows in frosting before adding them to the top of a chocolate cake. I applied that technique to my favorite Texas sheet cake recipe (doubling the frosting to make sure I had enough to coat the marshmallows) and it was DIVINE. Ridiculously rich— I mean, it has twice the amount of frosting! One of the best cakes we ever had and has been a family favorite ever since.
After one slice it’ll be hard to ever imagine eating any other kind of cake!
Rocky Road Texas Sheet Cake
The ingredients are basic:
Cake: Flour, sugar, cocoa powder, salt, and baking soda. You’ll also need butter, vinegar, eggs, milk, water and vanilla. You probably have most of these ingredients on hand.
Frosting: Butter, powdered sugar, cocoa powder, milk, vanilla, and chopped nuts.
Marshmallows: You’ll also need a bag of mini marshmallows (about 6 cups).
If you’re wondering about the whisk used in my video, it’s a Danish dough whisk and I use it for so many recipes! I rarely pull out my kitchen mixer for bread or batters.
The technique for making the cake and frosting is similar. You’ll melt the butter with the cocoa powder and a bit of liquid to make a chocolate syrup mixture that will be stirred into your dry ingredients. So once you finish the cake, give your saucepan a rinse and get ready to do the same thing with the frosting!
While the cake bakes, mix up the frosting so that it’s ready to pour over the hot cake. Toss the mini marshmallows in the frosting mixture, pour over the cake then sprinkle with nuts. Ooey, gooey perfection. As it cools, the frosting will set up, making it easier to serve, but it will still be soft.
This cake is so rich, a little goes a long way! I cut my classic Texas sheet cake into 15 portions, but this one goes a lot farther. Cut 4 rows, then 8 rows, for 32 slices.
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Rocky Road Sheet Cake Recipe
Rocky Road Texas Sheet Cake
- 2 cup all purpose flour
- 2 cup white sugar
- 1 teaspoon salt
- 1 cup butter
- 1 cup water
- 1/3 cup baking cocoa (cocoa powder)
- 2 eggs
- 1/2 cup milk
- 1 Tbsp. vinegar
- 1 teaspoon baking soda
- 1 teaspoon vanilla
- 1 cup butter softened
- 2/3 cups baking cocoa
- 2 teaspoon vanilla
- 2/3 cups milk
- 7 1/2 cups powdered sugar sifted
- 1 bag mini marshmallows 6 cups
- 1 cup nuts chopped
- Preheat oven to 350 degrees.
- Mix flour, sugar, and salt in a large bowl. Set aside.
- Heat butter, water, and cocoa powder in a sauce pan over medium heat. Stir as butter melts. Bring to a simmer then remove from heat.
- Slowly pour the butter/chocolate mixture over the dry ingredients. Stir.
- Mix eggs, milk, vinegar, baking soda and vanilla together in a small bowl. Add to the large bowl and mix until combined.
- Pour batter into a greased 12" x 17" baking sheet.
- Bake for 25 minutes.
- Heat butter, cocoa powder, vanilla and milk in a saucepan until butter has melted. Pour over powdered sugar and beat with electric mixer until smooth. Stir in marshmallows.
- Spread frosting over hot cake. Do your best to have an even layer of frosting (the marshmallows make this a little tricky, but it will be just fine!) Sprinkle with nuts.