If you've ever had a supermarket sheet cake, you've tasted American buttercream: a simple frosting made with little more than butter* and powdered sugar. For some, its simple sweetness and one-note vanilla flavor taste like pure nostalgia, recalling the pleasure of scoring a corner piece piled high with buttercream roses in implausible colors. For others, it's a flavor associated with scrunched up noses and the messy task of scraping off unwanted frosting to get at the pristine cake below.
Full disclosure: I fall into the latter group myself, and frosting was never really my thing until I discovered European-style buttercream in culinary school (universally made without powdered sugar). But I'm also the sort of person who understands that bad ingredients and technique can ruin even the most delicious dessert, and that American buttercream can be flat-out amazing with a little attention to detail.
*Note: Well, let's be honest. In the case of supermarket frosting, we're talking about shortening and imitation butter flavoring, but you know what I mean.
Swiss Buttercream Versus American Buttercream
My go-to European-style frosting is Swiss buttercream. It's a meringue-based frosting made from sugar and egg whites that are first cooked over a water bath, then whipped into an airy meringue, and ultimately enriched with butter. The meringue dissolves the sugar, making it smooth as silk while diluting the richness and heaviness of the butter. Since the eggs are fully cooked, it's more stable than Italian buttercream, but it can be problematic for folks with egg allergies, or on those occasions when a baker simply runs out of eggs.
American buttercream is nothing but powdered sugar moistened with butter. That kind of simplicity makes it quick and easy, but it also means that American buttercream tends to have a tooth-aching sweetness and density. Still, its egg-free formula is alluring for those with egg allergies, and the no-fuss approach makes it easy to whip up for last-minute desserts ("What, no, I didn't forget your birthday!").
American Buttercream Ratios
The majority of American buttercream recipes take a "more is more" approach with a 1:2 ratio of butter to powdered sugar by weight, while others use a 2:3 ratio to dial back the sweetness.
But that ratio can be dropped all the way down to a 1:1 combination of butter and powdered sugar, and it will still produce a thick and fluffy frosting. Aside from cutting back on the sweetness, using a lower proportion of powdered sugar results in a softer buttercream that's easier to spread over cake without pulling up crumbs.
Making American Buttercream Less Sweet
Especially for those already on the fence about American buttercream, starting with a tapioca starch–based organic powdered sugar will improve the overall flavor and texture of the frosting more than any other trick.
I've covered the differences between conventional and organic powdered sugar before, but to recap: while conventional powdered sugar is fully refined, giving it a truly neutral sweetness, organic powdered sugar starts with sugar that still contains a portion of its natural molasses content. That inclusion tempers how we perceive its sweetness, while creating a subtle depth of flavor.
Traditionally, powdered sugar is cut with 3 to 5% cornstarch to prevent clumping, but even in amounts that small, the particle size and insolubility of cornstarch can create some textural issues (like grittiness or chalkiness) in raw, low-moisture recipes. Organic powdered sugar, on the other hand, tends to be based on tapioca starch, which has a finer texture and better solubility. The result is a powdered sugar that seems smoother and creamier in no-cook frostings like American buttercream.
Thanks to those subtle shifts in flavor and texture, organic powdered sugar made with tapioca starch can offer huge improvements in a recipe as simple as American buttercream, where the quality of each ingredient can really stand out.
How to Make American Buttercream
At its core, American buttercream is nothing more than powdered sugar and butter, doctored to taste with salt and vanilla (another make-or-break ingredient for a frosting this simple; more on that in our guide to vanilla extracts).
As with any buttercream, ingredient temperature plays a huge role in the texture and volume of the final product. When the butter is too cold (below 65°F/18°C ) the frosting will be dense, stiff, and greasy. When the butter is too warm (above 70°F/21°C), the frosting will be soft, runny, and unstructured.
It's a narrow window, so I like to aim on the low end, with butter around 65°F (18°C). Beating the butter on a stand mixer fitted with a paddle attachment creates friction, slowly warming the butter as it whips, allowing it to expand with air. Properly done, the difference is dramatic.
So take your time along the way—the length of time needed to reach a truly light and fluffy state will vary depending on the power of a given stand mixer, as well as the temperature of both your ingredients and the room.
After the buttercream is fully aerated, I beat in a little cream (25% of the butter by weight). Having a liquid element in the frosting helps dissolve the powdered sugar, and while many recipes accomplish that with a splash of milk, cream lends a welcome flavor and richness to the frosting while helping it aerate even more.
When it's finished, the buttercream will be creamy and thick, but spreadably soft and ultra light. Lighter, in fact, than a Swiss or Italian buttercream, at around five and one quarter ounces per cup.
Once finished, the buttercream can be seasoned to taste with additional salt and vanilla (or a few drops of another extract), or a touch of food coloring if you're feeling festive. I prefer using concentrated gel pastes such as Americolor, rather than the watery dyes more commonly sold in supermarkets.
Whether used as a quick frosting for a sheet cake, or to crumb coat a layer cake, American buttercream should be used while freshly whipped and easy to spread.
It may not be the most sophisticated buttercream in the pastry realm, but with the right ingredients and technique, American buttercream can be just as creamy and light—a worthy part of any baker's repertoire. And given the speed and simplicity with which it comes together, it's one you'll reach for when you least expect it.