My mother has been gone a long time, but her recipe for caramel frosting remains on the refrigerator. She made it for every birthday cake. I learned to make it, too. It’s not terribly different from the “Caramel Ganache” in older versions of Joy of Cooking, except my mom usually made it with milk, not cream, which JoC calls for. It’s just as good, and even richer with cream, but given how much butter and sugar is in it anyway, the cream isn’t strictly necessary.
This recipe, in my mother’s handwriting, is just a shorthand for what it takes to make it. This version also reveals that she used cake from a mix, perhaps a true chef’s no-no. But I would argue that with frosting this rich the cake itself is a bit overwhelmed, so it doesn’t really matter if it is from a mix so long as the cake isn’t dry.
Here’s the recipe with a little more detail and instruction.
1 stick of butter (I use salted butter)
1 cup light brown sugar, firmly packed (we always used light brown, never dark)
1/4 cup milk (whole milk is best as skim tends to be too watery, but if you’ve got half-and-half or cream around, use it (!), but just know the icing will be a little thicker so use a “smidge” more half-and-half or cream than milk)
3 and 1/4 cup sifted powdered sugar (I’m lazy so I seldom actually sift, which means I make up for it in the mixing, not always to the best effect. My mother always sifted. And she was right to do so.)
Melt the butter in a medium pot or deep saucepan on medium heat. Just as it is completely melted stir in the brown sugar with a wooden spoon until it melts in. Keep stirring and regulate the heat. You want to bring it to a full boil for just 1 minute, then turn off the heat.
If you’ve made it in a big enough pot, you can add the powdered sugar right in which keeps everything warm and makes mixing a little easier, but if you’re using a Kitchenaid you’ll want to transfer the butter/brown sugar mix to a bowl for mixing. Make sure to get as much of the butter/brown sugar out of the saucepan as you can, quickly, to the bowl, before it cools and hardens a bit.
Mix in the powdered sugar, slowly. I usually start adding and mix with just my wooden spoon at first, and then add in the beater/mixers after it gets a little too thick. In any case, don’t dump all the powdered sugar in at once. Keep mixing and stirring until it is well combined. Then keep mixing until there are no bits of unmixed powdered sugar and it is completely smooth. This all needs to happen pretty quickly as the frosting will harden. If for some reason it gets absolutely too thick to work with, add a few teaspoons of warm milk to thin it out.
It should smooth nicely and be a light caramel color. Have your cake ready because you need to pour it on immediately while it is warm. Pour and spread with your spatula.
The results might not be as pretty as buttercream or beautiful-but-tasteless fondant, but I promise you that after one bite, nobody will be complaining.