Did your granny ever make one of those cakes where, when she cut into it, the icing would crack and break off in deliciously huge chocolate fudge chunks that just melted in your mouth? Well, this boiled chocolate icing recipe is for you.

Grandma Pearl’s flaky chocolate icing is the stuff of legend in my family. She always topped fluffy white cakes with it. My brother used to ask for one of these special cakes for his birthday and as long as she was able, Pearl would come through! I loved seeing that aluminum cake dome show up at our house because we knew full well what was beneath it!

This is what the old folks call a “boiled chocolate icing recipe” because they cooked it in a saucepot on top of the stove and it had to come to a full rolling boil and stay there a minute or two until it was ready. The process is similar to making fudge but we don’t use a thermometer, relying on the clock instead. This old-fashioned chocolate icing hardens very quickly, so it’s easiest to use on a sheet cake, where you simply pour it over the cake while it’s still in the pan and allow it to cool.

The end result is a thick layer of chocolate frosting that breaks off into rich and decadent chocolate fudge chunks that melt in your mouth. It’s the perfect complement to a simply fluffy Texas sheet cake and I promise it’s easy to make. If you’d like the peanut butter version of this boiled icing, it can be found by clicking here.

If you want to check out some of my other frosting recipes check them out: 7-Minute Frosting, Creamy Chocolate Frosting, or Royal Icing.

Alright, who’s ready to make some life-changing boiled chocolate icing? Me!

Recipe Ingredients

A white cake mix that’s prepared in a 9×13 pan according to package directions and then cooled.
Shortening
Butter
Milk
Granulated sugar
Cocoa powder
Vanilla extract

You don’t need a chocolate bar, but one was visiting my house and wanted to be in the photo and I was like “Why not! It’s a chocolate day!” I do try to be inclusive.

Helpful Kitchen Tools

How to Make Boiled Chocolate Icing

In a large saucepot, combine sugar, milk, shortening, butter, and salt.

Bring to a rolling boil over medium-high heat, stirring constantly to prevent scorching.

Once it reaches a boil, let it boil for two to three minutes without stirring.

Remove from heat and immediately stir in vanilla and cocoa powder.

Beat until icing is smooth and starts to lose its shine.

Immediately pour the icing over the cooled cake and allow it to cool.

Isn’t this a beautiful sight? Grandma Pearl’s boiled chocolate icing.

Note that your boiled icing will go down into the sides of your pan some, but that is okay.

Once it’s cooled, cut and serve! This icing is a rare treat not often seen these days!

I sure do wish we could sit down and have a nice chat over slices of this cake!

Y’all have a great afternoon. Be blessed and be a blessing!

Storage

Store leftover frosted cake in an airtight container in the fridge for up to 1 week.

Tips for Success

The boiling of the icing is the most critical step. Make sure it comes to a rolling boil and then stay right there, timing it. I suggest adding one minute to be on the safe side but don’t go over this as the icing will scorch.
Your cake must be ready the moment the icing is ready.
Once you finish your icing, remove it from the heat and use a wire whisk to quickly stir in your cocoa powder and vanilla, stirring until it thickens a bit and starts to lose some of its shine. It should still be pourable.
Don’t try to spread the icing once you pour it over the cake. Instead, pour it evenly over the cake so that you don’t need to spread it.
Most important tip of all: unless you lived through the Great Depression, I strongly encourage you not to use this on anything other than a sheet cake or brownies baked in the same size baking dish. Only those who have the crown of wisdom that comes through age and hardship can ice a layer cake with this.

Recipe Notes

These photos are for a single boiled frosting recipe. HOWEVER, the final cake pictured has a double recipe. If you want a nice and thick icing you’ll need to double it. If you want to see what a regular portion of icing looks like, click here to see it on my old-fashioned peanut butter icing post. These recipes are twins, with just one ingredient different.
While I haven’t tried it this way myself, I know some folks make boiled chocolate frosting with buttermilk and evaporated milk.
People have also said they’ve doubled the butter when out of shortening and it turns out perfectly too.