Back when I was learning to cook (and believed you couldn’t make a cake without cake mix), we didn’t have any of this fancy ready-to-use frosting in a plastic can. No, we used . . . frosting mix. (Really. You can still find it in some stores.)
Of course, ready made frosting is quick and easy to use and comes in enticing flavors. It’s also expensive and highly processed, and can be replaced with homemade buttercream icing. That’s just a simple mixture of butter and powdered sugar. (About a cup of butter to three cups of sugar — it’s adjustable.) Okay, the mixture isn’t that simple. You should throw in a spoonful or two of vanilla. And you may have to add milk to make it spreadable. But that’s it, after a few minutes with an electric mixer.
Buttercream is the classic option, but there are others besides running to the store for a can of frosting, or just sprinkling powdered sugar on your cake and letting it go at that (though it’s better than nothing).
For example, here’s a recipe for frosting made with Jello mix. (Caution: You do have to be able to separate an egg.) The Jello both flavors the icing and helps it set up.
I made a variation of this last weekend with a box of Jello, a cup of sweetened condensed milk, a half cup of boiling water, and a lot of Triple Sec. (It was for a grown-up’s birthday cake.) I’ve found both kinds of Jello frosting benefit from a couple of hours in the fridge before you frost the cake.
I’ve also had good results mixing condensed milk with True Lime crystals. You could try cocoa or melted unsweetened chocolate this way.
Then again, if you want to use chocolate, you might want to make ganache, which is just chocolate melted in heavy cream. Heat a cup of cream and eight ounces of semi-sweet baking chocolate (or 1 1/3 cup of chocolate chips) together into a smooth sauce, and pour it over the cake while it’s still warm.
Something very easy is a glaze made out of powdered sugar and just a little liquid (like lemon juice or milk). You can also combine a few spoonfuls of powdered sugar or brown sugar with sour cream or yogurt — though this makes something more the texture of whipped cream than of frosting.
It’s your cake — it can be your frosting too.