Hot Fudge Cake is a deliciously rich chocolate cake with a hot fudge sauce that forms underneath the cake while baking for the perfect, magical chocolate dessert! 

Take this hot chocolate fudge cake over the top, by serving it with a scoop of vanilla ice cream and drizzled with homemade hot fudge sauce or with a dollop of Nutella whipped cream

A square white dish with hot fudge cake in it.

Why This Recipe Works

  • Magically makes a chocolate sauce. This recipe is so much fun because the cake magically makes its own chocolate sauce while baking in the oven. The hot water mixes with the chocolate sugar mixture and settles at the bottom of the baking dish while the baking powder in the cake mixture helps the cake rise — literally — to the top of the pan. 
  • Delicious chocolate gooey goodness. This cake is super moist and delicious thanks to the gooey delicious sauce that is formed. The self saucing aspect of the cake keeps the cake part very moist. 
  • Easy cake prep. I love this recipe because it only takes 15 minutes to prepare! The rest of the work is done in the oven. 

Ingredient Notes

Ingredients used to make Hot Fudge Cake portioned into glass bowls on a white and cream textured background.
  • Granulated Sugar: The granulated sugar is used in the cake batter and in the chocolate sugar mixture that forms the sauce. 
  • Flour: Magically, the sauce that is formed in the oven combines with some of the flour from the cake batter so the sauce thickens while baking. 
  • Natural Cocoa Powder
  • Baking Powder: The baking powder is important because it not only helps give rise to the cake but it also helps the cake batter rise to the top of the dish so the sauce settles underneath it.
  • HOT Water: The hot water helps bloom the cocoa and it also creates heat to activate the self-saucing process.

Step-by-Step Instructions

  1. Make the cake batter. Combine 3/4 cup of the sugar, 1/4 cup of the cocoa powder, the flour, baking powder, and salt. Stir in the milk, melted butter and vanilla. Beat the mixture with a hand mixer until smooth.
A glass bowl with dry ingredients in it, including baking powder, for making hot fudge pudding cake.
  1. Place in the pan. Spread the batter in a 9-inch square baking pan that has been sprayed with cooking spray.
A brown hot fudge cake batter in a white square pan.
  1. Make the sugar mixture. Combine the remaining sugar and cocoa powder, and the brown sugar in a small bowl. Sprinkle this mixture evenly over the batter.
A brown colored sugar mixture overtop a hot fudge cake batter in a white square pan.
  1. Add HOT water. Pour the HOT water overtop. Do NOT stir!
A square white pan with boiling water poured overtop a hot fudge cake batter.
  1. Bake the hot fudge cake. Bake the cake at 350°F for 32-35 minutes or until the center is almost set. Remove from the oven and let stand for 10 minutes. Serve the cake in individual dishes topped with ice cream or fresh whipped topping. Drizzle extra homemade hot fudge sauce overtop if you’d like!
A close up photo of hot fudge cake removed from a baking dish, leaving behind the cake crumbs and hot fudge.

Recipe Tips

Since this is a self saucing chocolate cake recipe, the toothpick in the center of the cake won’t give you much help on if the cake is baked. So, when checking on the hot fudge cake, it will be done when the center of the cake looks almost set. Remember, you let the cake sit for an additional 10 minutes once you’ve removed it from the oven. So it will continue to bake a bit from the residual heat from the pan. 

This hot fudge chocolate cake has the chocolate sauce in the bottom, so don’t be alarmed by thinking the cake is under baked if you fit a toothpick in it and it comes out saucy. You know it’s perfect when the hot chocolate cake on top is set and the fudge sauce pools when you serve it. 

It will seem like a lot of water you are adding on top, but don’t be alarmed! This cake works wonders in the oven. And while it’s baking, the chocolate sauce mixture will combine with some of the cake mixture and it will thicken — this is how we get the fudge-y texture of the sauce instead of just a liquidy sauce. 

Carefully pour the water over the chocolate/sugar mixture. You don’t want to pour with such force that you create a hole or dip in the sugar mixture or cake batter underneath. I like to pour the water slowly and move my hand around the pan so the water isn’t just pouring into one spot. 

If you’re wanting to double the recipe, I would recommend making the cake two times in two separate pans. Because of the technicality of the self saucing process in the oven, doubling this cake and baking in a bigger cake pan won’t guarantee a correct bake. 

Variations: Add a dash of cinnamon to the cake batter for a Mexican hot chocolate twist. Add some chopped walnuts to the cake batter for a bit of crunch. 

Serve this hot chocolate cake with ice cream, whipped cream, chocolate sauce, caramel sauce, and more! 

Hot Fudge Cake on a white plate with a scoop of ice cream and hot fudge sauce drizzled overtop.

Make Ahead, Storing, and Freezing

Making this hot fudge cake recipe ahead of time is kind of hard because you want to eat it warm, after you remove it from the oven to get that self saucing chocolate pudding effect. 

Store any leftovers covered in the fridge for 1-3 days. The cake is much better fresh, but leftovers are still yummy! Warm them up a bit in the microwave before eating again. 

I don’t recommend freezing this cake due to the fudge sauce that forms on the bottom. 

FAQs

How do self saucing cakes/puddings work?

It’s chemistry at work! The cake batter mixture has baking powder in it. When that bakes, it rises to the top of the dish and the heavier sauce mixture settles to the bottom. It’s definitely a fun baking experiment because it seems like magic!

Can I use dutch process cocoa powder?

I haven’t used dutch process cocoa powder in this recipe, and since the cocoa powder isn’t acidic like natural/unsweetened cocoa powder is, I’m not sure how the self-saucing process of the bake will be affected. 

Why isn’t the water sinking to the bottom?

This could be that your water wasn’t hot enough to begin with or that the oven temperature was off. I always use an oven thermometer to ensure my oven is at the correct temperature. Some ovens can run hotter or cooler. If those tips don’t help, then I would recommend gently pouring the water on top of the sugar mixture so you don’t form a hole or dip in the mixture or cake batter — that could throw off the self saucing process. 

Overhead photo of hot fudge cake on a plate topped with a scoop of vanilla ice cream.

More Chocolate Recipes

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Hot fudge cake on a plate topped with ice cream and hot fudge sauce.
Print Review
5 from 8 votes

Hot Fudge Cake

Hot fudge sauce forms under a rich chocolate cake making for a perfect chocolate dessert!
Prep Time: 15 mins
Cook Time: 35 mins
Total Time: 50 mins
Servings: 9 1/2 cup servings

Ingredients
 

  • 1 1/4 cup granulated sugar - divided
  • 1 cup all purpose flour
  • 2/3 cup natural cocoa powder - divided
  • 2 teaspoon baking powder
  • 1/4 teaspoon salt
  • 1/2 cup milk
  • 1/3 cup unsalted butter - melted
  • 1 1/2 teaspoon vanilla extract
  • 1/2 cup brown sugar - packed
  • 1 1/4 cups HOT water

Instructions
 

  • Preheat oven to 350°F. Spray a 9-inch square baking dish with cooking spray. Set aside.
  • In a large bowl combine ¾ cup granulated sugar, flour, ¼ cup cocoa powder, baking powder, and salt. Stir in the milk, melted butter, and vanilla. Using hand mixer, beat mixture until smooth. 
  • Pour the batter into the 9-inch baking dish. 
  • In a small bowl, combine the remaining ½ cup granulated sugar, remaining cocoa powder, and the brown sugar. Sprinkle this mixture evenly over the batter. 
  • Pour the hot water overtop. Do not stir!
  • Bake for 32-35 minutes or until center is almost set. Remove from the oven and let stand for 10 minutes. 
  • Serve in individual dishes. Top with ice cream or fresh whipped topping.

Notes

Making this hot fudge cake recipe ahead of time is kind of hard because you want to eat it warm, after you remove it from the oven to get that self saucing chocolate pudding effect. 
Store any leftovers covered in the fridge for 1-3 days. The cake is much better fresh, but leftovers are still yummy! Warm them up a bit in the microwave before eating again. 
I don’t recommend freezing this cake due to the fudge sauce that forms on the bottom. 
Carefully pour the water over the chocolate/sugar mixture. You don’t want to pour with such force that you create a hole or dip in the sugar mixture or cake batter underneath. I like to pour the water slowly and move my hand around the pan so the water isn’t just pouring into one spot. 
For troubleshooting and FAQs, see my blog post. 
recipe source: adapted from Hersheys.com

Nutrition

Calories: 290.36kcal (15%)Carbohydrates: 55.21g (18%)Protein: 3.2g (6%)Fat: 8.27g (13%)Saturated Fat: 5.11g (26%)Cholesterol: 19.43mg (6%)Sodium: 77.53mg (3%)Potassium: 235.87mg (7%)Fiber: 2.49g (10%)Sugar: 40.5g (45%)Vitamin A: 232.06IU (5%)Calcium: 76.22mg (8%)Iron: 1.69mg (9%)
Course: Dessert
Cuisine: American
Did you make this recipe?Leave a star rating and review on the blog post letting me know how you liked this recipe! Take a picture and tag @saltandbaker on Instagram and Facebook so I can see what you’re making!

This recipe was originally published on Dec. 20, 2019. It was republished on Feb. 10, 2022, to include additional information and photos.