Fudge Frosting And Chocolate Buttercream Are Not The Same. Here's Why
Understanding the difference between fudge frosting and chocolate buttercream might seem trivial to you, but if you want to produce the perfect cake, it pays to get it right. We accept that there is an amazing amount of diversity in baking ingredients, like different flours or chocolates, that deserve exploring and explaining, but frostings don't get the same attention. After all, you're just pouring liquid sugar over something, how much thought does that require? Well, there are a lot of types of frosting out there, and cooks don't add things to recipes without thinking they will make a meaningful difference. And when recipes list fudge frosting instead of chocolate buttercream, they mean it.
There are two main things that set fudge frosting and buttercream frosting apart, and they both reflect their namesake recipes. Compared to chocolate buttercream, fudge frosting usually has a more intense chocolate flavor, and it should also have a denser texture. The confusion between the two is understandable, because they can have nearly identical ingredients, and are usually prepared in very similar way. But the end goal you are aiming for with fudge-style frosting is a richer, more chocolaty, and decadent frosting. This is achieved more through the way you handle the ingredients and the styles of chocolate used when mixing them. With that in mind, the point at which chocolate buttercream becomes rich enough to be fudge frosting is going to come down partially to personal taste.
Fudge frosting is richer and less fluffy than chocolate buttercream
Fudge frosting is still mostly a buttercream frosting. Both get their texture by mixing butter and sugar together to create a creamy base that's combined with chocolate and other flavors. Both will also usually have added milk or cream to help create a smooth texture. The first big divergence is in what type of chocolate you use and how much. Because chocolate buttercreams are aiming for a light, fluffy texture and sweeter flavor, they usually call for cocoa powder. The dry cocoa powder incorporates into the whipped buttercream easily without it collapsing and losing air. In fudge frosting recipes, you are more likely to use melted chocolate bars or chips. The thick melted chocolate will weigh down the cream more, leading to the desired fudgy texture.
The second is in how the chocolate and butter are mixed. Fudge frosting can be made by whipping the butter and sugar until fluffy, like in a chocolate buttercream, because adding melted chocolate will still make it richer. However, many fudge frosting recipes use the same ingredients, but add the butter and sugar directly to the melted chocolate without whipping. This results in an even thicker and more decadent texture. So you can prepare a fudge frosting that is halfway to chocolate buttercream, just a little more heavy, or you can choose one that goes all in on gooey fudginess. There are no wrong answers here, just whatever works best with your favorite decadent cake recipes.