Long before plastic wrap, bakers kept cakes fresh by covering their exterior with frosting, a sweet, spreadable topping that would seal the pores of the cake to minimize moisture loss. In the olden days, this was most commonly a very thin layer of hard meringue, which made the cakes look pretty cool, literally, as if they were covered by a layer of crackly frost or ice (hence the terms frosting and icing).
Nowadays, frosting is something of an umbrella term used to describe just about anything spread over the exterior of a cake, which has led to a mind-boggling number of recipes that technically qualify as frostings. Raspberry whipped cream? That's a frosting. Whipped ganache? Also a frosting. Swiss meringue? Frosting. American buttercream? You got it: frosting.
The variety may seem a little ridiculous at first, but that only translates to more flexibility in the kitchen. Whether you've run out of powdered sugar, have an egg allergy to deal with, or simply need to use up a jar of honey, there's a frosting that will cater to your needs.
While this is by no means an exhaustive overview of frosting styles, it's a good look at the major players, including the advantages and disadvantages of each as well as special points of consideration in terms of usage and technique.
Swiss Meringue Buttercream
Swiss buttercream is the workhorse of a pastry chef's kitchen, a cheap and easy frosting made from egg whites. With a bit of sugar thrown in, the mixture is cooked over a water bath, whipped into an airy Swiss meringue, then enriched with butter. The result is a silky smooth frosting that tastes light and mild, ready to be customized for any occasion or stored away for later—Swiss buttercream is outrageously stable, able to be frozen, thawed, and re-whipped as needed.
Why it's great: Swiss buttercream is versatile and fast, ready in 30 minutes or less.
What flavors work best: Thanks to its sweet and simple meringue base, Swiss buttercream goes with just about everything.
What to avoid: High-moisture ingredients, such as cream cheese, sour cream, mascarpone, fresh fruit purée or juice, beer, wine, tea, liqueur, coffee, honey, and maple syrup as well as any sort of syrup or sauce.
How to customize: The sugar in Swiss buttercream can be replaced, in whole or in part, with an equal weight of toasted sugar as well as any type of raw or semi-refined sugar, such as jaggery, turbinado, demerara, or plain brown sugar (dark or light). Or, doctor the finished buttercream to taste with potent, low-moisture ingredients, such as dark chocolate, espresso powder, peanut butter, virgin coconut oil, freeze-dried fruit, pure extracts, and essential oils.
Italian Meringue Buttercream
Like Swiss, Italian buttercream is based on meringue. But instead of one that's fully cooked on the stovetop, the raw egg whites are warmed by the addition of hot sugar syrup. The heat helps them whip up lighter than they would when cold, but it doesn't quite cook them through. Aside from that small detail, Italian behaves almost identically to Swiss in every way.
Why it's great: Because stovetop cooking reduces the moisture content of liquid sugars like maple, honey, and golden syrup, Italian works well with sweeteners that would otherwise destabilize a Swiss meringue.
What flavors work best: Those based on liquid sugar, such as honey, agave, maple, or light molasses.
What to avoid: Some liquid sugars, like blackstrap molasses, may be unexpectedly bitter or high in sodium, so take care when experimenting with concentrated flavors.
How to customize: Flavor to taste with potent, low-moisture ingredients such as dark chocolate, espresso powder, peanut butter, virgin coconut oil, freeze-dried fruit, pure extracts, and essential oils.
Thanks to a foundation of whipped egg yolks, this style is especially creamy and thick, with a rich and custardy flavor and deep-yellow hue. Like its Swiss cousin, French buttercream is fully cooked when prepared over a water bath, making it just as stable in terms of shelf-life, usage, and customization.
Why it's great: Sick of lemon curd? French buttercream can plow through a bowl of leftover egg yolks like nobody's business! And with the right ratios and cooking method, it's as light, creamy, and stable as any other.
What flavors work best: Because it has so much character of its own, French buttercream needs bold, aromatic flavorings that can stand up to those custardy yolks: think aromatic spirits, zesty citrus, and bold spices. Any flavors that would appeal to you in a frozen custard or sabayon should translate well to French buttercream—think cinnamon, vanilla, lemon, pistachio, espresso, or dark chocolate.
What to avoid: Because it's made with egg yolks and butter, French buttercream may seem greasy when paired with high-fat ingredients, such as white chocolate, black sesame paste, and so on. As with Swiss, it's not suited to liquid sugars, such as honey, molasses, or maple syrup.
How to customize: French buttercream can be made with toasted sugar or any type of raw, semi-refined, or brown sugar. Since the recipe includes an ounce of liquid to help dissolve the sugar, French buttercream is easily spiked with flavorful spirits and liqueurs, concentrated liquids like espresso and strongly brewed tea, or even lemon juice. Like any buttercream, it can be flavored to taste with a few drops of extract or essential oil whipped in at the end.
Unlike French, Swiss, or Italian buttercream, German buttercream starts with homemade vanilla pudding rather than whipped eggs. This gives it a dairy-forward flavor that's creamy and mild.
Why it's great: With its milky custard base, German buttercream has an ice cream–like quality that pairs beautifully with cake.
What flavors work best: Any unwieldy ingredient that would be difficult to incorporate into other buttercream styles without affecting their texture, such as coffee beans, whole spices, loose-leaf tea, hearty herbs, and low-acid fruits like banana.
What to avoid: Acidic ingredients of any kind.
How to customize: Add flavorful ingredients to the warm milk, cover, and steep to desired intensity, then strain. Be sure to re-measure the milk and top it off as needed, as some ingredients may absorb a few ounces of the milk.
Why it's great: There's no arguing with the speed and simplicity of American buttercream or the allure of an eggless alternative to Swiss. Because it's comparatively thick and stiff, it pairs well with cookies, whether used as a filling or frosting.
What flavors work best: Because it's not cut with a meringue, American buttercream can be sweeter than other frostings, so it works well with tart or bitter flavoring agents like lemon extract or instant espresso.
What to avoid: High-moisture ingredients, such as fresh fruit purées, coffee, and liquid sugars like agave as well as any sort syrup or sauce.
How to customize: Because of its simplicity, American buttercream can be quite fickle when it comes to added ingredients. For best results, stick with extracts, flower waters, essential oils, and powdered flavorings like instant espresso. Some of the butter can be replaced with more flavorful alternatives, like peanut butter or cream cheese, but take care as these may also introduce instability.
Flour-frosting, also known as ermine frosting, is an old-school buttercream made with just four ingredients: butter, sugar, flour, and milk (okay, six ingredients, if you count salt and vanilla). It feels as light and silky as whipped cream, with a flavor that's equally simple and mild.
Why it's great: Its strong, dairy-forward flavor reminds me of a lightly sweetened whipped cream, and it's a wonderful eggless alternative to German buttercream. Because the sugar is added to the milk off-heat, ermine frosting works with acidic sweeteners, like brown sugar, that could cause German buttercream to curdle.
What flavors work best: Thanks to its milky flavor and mild sweetness, ermine pairs best with straightforward flavor profiles that benefit from a sense of creaminess, such as vanilla, almond, coconut, or mint.
What to avoid: High-moisture ingredients such as fresh fruit purées, brewed coffee, and liquid sugars like agave as well as any sort syrup or sauce. Because of its relatively low-sugar, high-moisture composition, flour frosting has a shorter shelf life than other buttercreams; for this reason, it's not a great make-ahead recipe and may spoil quickly in a warm environment.
How to customize: Swap the white sugar with an equal weight of light brown sugar, toasted sugar, or semi-refined sugars such as muscovado or demerara, if they're finely ground. As with other buttercream styles, low-moisture flavorings like powdered espresso, pure extracts, and essential oils work well as flavoring agents in ermine frosting.
Why it's great: With only two ingredients—chocolate and cream—whipped ganache is a bold but simple choice that puts top-notch chocolate center stage.
What flavors work best: Milk chocolate brings a mellow sweetness to whipped ganache frosting, making it a perfect partner for cake.
What to avoid: Cheap milk chocolates that are cut with palm oil or other fats besides cocoa butter.
How to customize: A frosting like this is only as good as the chocolate in question, so customization comes from finding a brand with a profile you love. Explore different styles and intensities of chocolate, with varying percentages of cocoa butter, to find the sort you love best.
Why it's great: Whipped cream is classic, simple, and perfect for last-minute cakes. When made in a food processor with freeze-dried fruit, whipped cream takes on a denser, more frosting-like texture that makes it especially stable as a topping for cake; it also takes on an outstanding color and flavor.
What flavors work best: Any potent, low-moisture ingredient that can be added in small doses or via infusion.
What to avoid: Whipped cream frosting isn't a great choice for picnics, pot lucks, or any outdoor gathering where elevated temperatures may destabilize the whipped cream as it sits out over time.
How to customize: All sorts of sweeteners, from demerara to toasted sugar (or even options like cajeta or lemon syrup ) work well in classic whipped cream, as do pure extracts, essential oils, and powdered flavorings like instant espresso or freeze-dried fruit. For those willing to invest the time, the cream itself can be infused with anything from herbs to vanilla pods and coffee beans or even cherry pits.
This is basically Swiss buttercream, minus the butter—a light, creamy, and old-school approach to frosting.
Why it's great: This lean frosting is a nice way to balance out a super-rich cake or to lighten the profile of a dessert that's meant to follow a heavy meal. Plus, it can be brûléed with a blow torch for a toasted, s'mores-like experience that's perfect with chocolate cake.
What flavors work best: Because oil-based extracts and flavorings may deflate the meringue, it's best to stick with water and alcohol-based extracts or powdered flavoring like instant espresso powder or freeze-dried fruit.
What to avoid: High-moisture ingredients, such as cream cheese, sour cream, mascarpone, fresh fruit purées or juices, beer, wine, tea, liqueur, coffee, honey, and maple syrup as well as any sort of syrup or sauce.
How to customize: The sugar in the meringue can be replaced, in whole or in part, with an equal weight of toasted sugar as well as any type of raw or semi-refined sugar, such as jaggery, turbinado, demerara, or plain brown sugar (dark or light). Or, doctor the finished buttercream to taste with potent, low-moisture ingredients, such as dark chocolate, espresso powder, peanut butter, virgin coconut oil, freeze-dried fruit, pure extracts, and essential oils.