Marshmallow Chocolate Cake (S’mores Brownies)

This Marshmallow Chocolate Cake (S’mores Brownies) is a deliciously decadent dessert that will satisfy your sweet tooth and impress your guests!

With rich & moist chocolate brownie cake, fluffy & crispy marshmallow topping, and nutty & crunchy walnut filling, this cake is the ultimate indulgence for any chocolate lover.

Marshmallow Chocolate Cake Trouble Shooting

Even though this marshmallow chocolate cake is one of the simplest desserts for beginner bakers to make at home – without the need for an egg whipping process – there are still potential issues that can arise.

In fact, it took me three attempts to perfect this cake recipe. During my first attempt, the marshmallows stuck to the cake mold badly. On the second try, I overheated the chocolate, resulting in an overly greasy cake. During the third attempt, I roasted the marshmallows for too long, causing them to become covercolored.

However, I’m grateful for these challenges because they allowed me to discover practical solutions to resolve them. Through my experiences, I hope to provide you with tips to ensure your marshmallow chocolate cake turns out perfectly on your very first try!

1. Why is my brownie oily?

From my baking experiences, I have observed that the selection of chocolate can influence the outcome of brownies.

Brownies made with 60% to 70% chocolate tend to turn out more successfully in my experience, while those made with 90% dark chocolate often end up being oily. Despite searching for scientific evidence to explain this phenomenon, I have yet to find any conclusive proof. Nonetheless, based on my personal experience with baking, I have come to this conclusion.

When chocolate is overheated, it can become oily or greasy because the cocoa butter in the chocolate separates from the cocoa solids. 

To prevent overheating and separation of cocoa butter, it’s important to turn off the heat and melt chocolate chips using the residual heat and stirring frequently.

Alternatively, you can use a double boiler. Specifically, you:

1. Fill a saucepan with a small amount of water and bring it to a simmer over medium heat.
2. Place a heatproof bowl on top of the saucepan, making sure the bottom of the bowl doesn’t touch the water. The bowl should fit snugly on top of the saucepan, creating a seal.
3. Add the butter and chocolate to the bowl and stir occasionally with a spatula until fully melted.

Be careful not to get any water in the chocolate, as this can cause it to seize and become lumpy.

2. How to prevent burnt marshmallows?

To stay on the safe side, after you make the chocolate cake base and line the marshmallows on the top, you just send the cake back to the oven to bake at 350°F (180°C) for 10 more minutes until the marshmallows are lightly browned.

If the marshmallows are not sufficiently browned after the baking process, you can use the “roast” mode of the oven to roast them for 30 seconds to 60 seconds. However, make sure you observe carefully during this step as an additional 5 seconds of roasting could lead to burnt marshmallows, ruining their perfect color.

3. How to prevent the marshmallows from sticking to the mold?

Heating marshmallows can cause them to become sticky, which is why can’t directly add them to the baked chocolate cake base. An easy method to prevent the marshmallows from sticking to either the parchment paper or the cake mold is to transfer the cake base onto a large baking sheet before placing the marshmallows on top.

4. Lava cake or brownie?

Lava cake, also known as molten chocolate cake, is a rich chocolate cake with a soft and gooey center. It is typically made by slightly undercooking the cake batter so that the center remains molten.

Brownies, on the other hand, are dense and fudgy chocolate cakes. They are made with a higher ratio of chocolate and sugar to flour, resulting in a more concentrated chocolate flavor.

By strictly following the marshmallow chocolate cake recipe, you will be able to bake a dense brownie cake with roasted marshmallows on top. However, if you desire a cake with a gooey, melted center, you can choose to omit the 10-minute baking step outlined in step 9 (detailed below), and instead roast the marshmallows for 1 minute until they are slightly browned. In this case, cutting open the cake will reveal a molten center that resembles flowing lava.

EQUIPMENT you will need:

• Cooking pan
• Mixing bowls
• loaf pan (My loaf pan is 8*4*3 inch (L*W*H). You can also use a round cake pan or a casserole dish.)
• Baking sheet
• Oven

INGREDIENTS List:

• 150 g unsalted butter (About ⅔ cup or 1⅓ sticks of butter)
• 200 g semi-sweet chocolate chips (About 1 cup of 60% – 70% chocolate chips)
• 5 eggs
• 50 g granulated sugar (About 3 tbsps; As we plan to include a layer of marshmallows on top, I suggest making the brownie cake less sweet. If you prefer the regular level of sweetness, you may add 5 tbsps of sugar here.)
• 1 g salt (About ¼ tsp)
• 110 g all purpose flour (About ¾ cup)
• 65 g chopped walnuts (About ½ cup; You can use any other nuts of your choice, such as pecans, hazelnuts, pistachios. Or you can skip the nuts.)
• 2 g orange zest (About 1 tsp. Optional.)
• 18 marshmallows

Step-by-step INSTRUCTIONS:

1. Preheat oven to 350°F (180°C). Line a loaf pan with parchment or foil paper.

2. In a medium-sized cooking pan, melt 150g butter over medium-low heat. Stir the butter with a spatula until it’s completely melted, then turn off the heat. Add 200g semi-sweet chocolate chips to the pan and stir continuously, allowing the residual heat of the pan to melt the chocolate chips. Stir until fully melted, set aside.

3. Add 5 eggs, 5 tbsps of granulated sugar, and a pinch of salt to a mixing bowl, whisk the ingredients together until they are thoroughly combined.

4. Pour the melted butter chocolate mixture to the egg mixture. Whisk until fully combined.

5. Add 110g all-purpose flour to the batter by sifting it into the mixing bowl. Use a spatula to blend the ingredients together until no dry flour can be seen.

6. Add ½ cup of chopped walnuts (or any other nuts of your choice) and 1 tsp of orange zest (optional) to the batter, blend with a spatula until they are evenly distributed.

7. Transfer the cake mixture to the parchment/foil lined loaf pan. Bake at 350°F (180°C) for 25 minutes. Remove the cake from the oven.

8. Lift the cake out from the loaf pan by lifting the edge of the parchment paper. Place the cake on a baking sheet, make sure that the parchment paper is lined underneath the cake.

9. Place the marshmallows on top of the baked chocolate cake until they completely cover the surface of the cake. Send the cake back to the oven to bake at 350°F (180°C) for 10 more minutes until the marshmallows are lightly browned.

• If the marshmallows are not browned to your liking, you can use the roast function of your oven for 30-60 seconds to achieve the desired color. Be sure to keep a close eye on the marshmallows when using the roast function, as they can quickly become over-colored.

10. Optionally drizzle with chocolate sauce. Enjoy hot.

Got some leftover marshmallows and don’t know what to make? It’s time to try this viral Korean torched marshmallow ice cream recipe.

My other cake recipes you will also like: