Grandma’s Hot Fudge Sundae Cake

Prep Time 10 minutes
Total Time 40 minutes
Servings 8 servings

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Grandma’s Hot Fudge Sundae Cake is a super easy cake that makes its own hot fudge sauce as it bakes! Perfect with ice cream.

I feel like we know each other well enough now that I can share with you a few family secrets. Like my Grandma’s Hot Fudge Sundae Cake.

It’s a really big deal.

white pie plate with grandma's hot fudge sundae cake and scoop missing

My grandma has made all of her granddaughters and granddaughters-in-law a cookbook, with recipes written out by hand and pictures from cooking magazines. She collects recipes from family members to contribute, so it is an amazing compilation of well-loved recipes.

This cake has been my favourite dessert for many, many, many years. Certainly all throughout my childhood. And as I’ve grown up and started experimenting more in the kitchen, I tend not to make the same recipe repeatedly because there are just so many that I want to try.

But I made some pork chops in the slow cooker, and they tasted great, they just didn’t look great. And I have a hard time wanting to share things with you guys that don’t photograph well. Because we eat with our eyes first, they say.

So after supper I was feeling like I should make something blogworthy, but I just didn’t have a lot of energy. I wanted something outstanding without putting in a ridiculous amount of time. And I didn’t want to mess around a lot with recipes I don’t know.

So it just made sense that I would share this with you today.

overhead image of white pie plate with metal spoon scooping cake

I made this entire cake, minus the baking, in the time it took my husband to unload and reload the dishwasher.

Not that it was a race.

(It was a race.)

bowl of hot fudge sundae cake with pie plate in the background

And it’s not like it took him a really long time. I’m telling you, 10 minutes max and you can have this baby in the oven. The ingredients are all simple: there’s nothing to be chopped, melted, sifted, whatever it is that takes extra time. It’s all about minimal effort and maximum wow factor.

This recipe is awesome for entertaining, too. You could make the batter, spread it in the pan, top with the brown sugar mixture and then cover with plastic wrap and let sit in the fridge until you’re ready to bake. Then just pour the hot water on top and bake.

close up image of hot fudge sundae cake with pie plate in the background

This cake has a chewy, almost brownie-like layer on the top and a thick, hot, rich chocolate sauce on the bottom. And it’s divine. Grab a tub of your favourite ice cream and go to town.

*NOTE: Some people have mentioned the sauce was very runny. This is the recipe we have used over and over again, and yes, this is the recipe used to make the cake in the pictures! There is a lot of fudge sauce when all is said and done — as it cools it will continue to set up. If you want more of a gooey chocolate cake and less a chocolate cake with chocolate fudge sauce, reduce the boiling water to 1 ½ cups. I have done this before, but I find that as it sits it doesn’t leave much sauce, so we like to stick to the full 1 ¾ cups.

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Grandma’s Hot Fudge Sundae Cake

4.67 from 9 votes
Delicious chocolate cake that makes its own hot fudge sauce while it bakes, right in the pan! This is amazing served with any flavour of ice cream: mint, vanilla, chocolate, strawberry — you name it!
Prep Time 10 minutes
Cook Time 30 minutes
Total Time 40 minutes
Cuisine American
Course Dessert
Servings 8 servings
Calories 271cal


  • 1 cup whole wheat flour or sub all-purpose
  • 3/4 cup sugar
  • 2 tbsp + ¼ cup unsweetened cocoa powder divided
  • 2 tsp baking powder
  • 1/4 tsp salt
  • 1/2 cup milk
  • 2 tbsp oil
  • 1 tsp vanilla
  • 1 cup packed brown sugar
  • 1 3/4 cup hot water


  • Preheat oven to 350 degrees F.
  • In a medium bowl, combine flour, sugar, 2 tbsp cocoa, baking powder, salt, milk, oil and vanilla. Batter will be very thick — don’t fear. You might need to stir with a metal spoon.
  • Spread batter into a greased 9″ pie plate or square pan (*Note: make sure your pan has tall sides, otherwise your cake might run over a bit.)
  • Combine brown sugar and ¼ cup cocoa. Spread over batter.
  • Top with hot water (I use freshly boiled). Bake for about 30-35 minutes until top is dry and puffed. (*Note: put a cookie sheet underneath your pan in the oven, just in case a little spills over).
  • Serve warm with ice cream.

Nutrition Information

Calories: 271cal | Carbohydrates: 57g | Protein: 2g | Fat: 4g | Cholesterol: 1mg | Sodium: 91mg | Potassium: 237mg | Fiber: 1g | Sugar: 46g | Vitamin A: 25IU | Calcium: 101mg | Iron: 0.8mg

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Meet Ashley

My name is Ashley Fehr and I love creating easy meals my family loves. I also like to do things my way, which means improvising and breaking the rules when necessary. Here you will find creative twists on old favorites and some of my favorite family recipes, passed down from generations!

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  1. Cathy H says

    Easy and delicious. It is very rich and chocolaty. The sauce thickens as it cools. Like the recipe just as it is written. Many chocolate cobblers use a lot of butter and sugar. This recipe uses lots of sugar but only 2 T of oil.

  2. Natalie H. says

    Can this be made with dutch process cocoa? Since the recipe uses baking powder, I would think this could be subbed instead of natural cocoa powder. It would definitely make a VERY rich chocolatey flavor.

    • The Recipe Rebel says

      Hi Natalie! I haven’t tried it myself so I can’t be sure. If you decide to experiment, let me know how it goes!

  3. Minerva says

    I’ve made this cake several times using a variety of plant-based milks and different oils. It’s never been a miss. This is my go-to for a chocolate fix!

  4. Miss Diane says

    My mother used to make that chocolate fudge pudding and I posted it on my blog in 2007. I make a gluten and lactose free version and it is very good.

    P.S. I am 73 yrs old so that recipe is very old…

  5. Traci Jarrett says

    Such ooey, gooey chocolatey yummines!! I can’t eat chocolate and it’s so difficult to find a recipe that doesn’t have peanut butter or bananas in it. Sometimes you just want a chocolate dessert!
    My next mission is mint chocolate, I may try and sub the vanilla for mint extract, we shall see ?

  6. Betty says

    I noticed on your grandma’s recipe, the word “walnuts”, but no mention in your you omit those???? I’m always “leery” of online recipes, because I’ve had them fail due to incomplete recipes…Please advise!!! Thanks!

  7. Abby says

    While this recipe did in fact work for me (which shocked me, really), it wasn’t very “chocolatey.” Next time I’ll sprinkle some chocolate chips on top of the batter before I sprinkle the brown sugar mixture on.

  8. Hamna Attique says

    Hello. I am baking it and it’s in the over for like 30 minutes but the top isn’t puffed up as you said in the recipe. What should I do?

  9. Aless says

    This was the first thing my now 30something kids taught themselves to bake!!! If I hadn’t made a dessert, they were eager to offer!! LOL!!

  10. Ashli says

    I think I goofed! Mine didn’t turn out at all—but two things against me…I live in the mountains over 7500 feet—the altitude often wreaks havoc on baking! The other is I decided to make it in a 8 x 8 glass pyrex dish. LOL help!

4.67 from 9 votes (5 ratings without comment)

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