Smooth American Buttercream

Before you start

American buttercream is the simplest frosting there is: softened butter beaten with powdered sugar, a little cream, vanilla and salt. It needs no stove and no eggs, it crusts lightly on the surface, and it holds a piped swirl at ordinary room temperature, which makes it the default for birthday cakes and cupcakes.

Its reputation for being gritty and cloying usually comes from technique, not the recipe. Sift the sugar to break up hard lumps, beat the butter alone until it is pale and fluffy before any sugar goes in, and keep beating after the last addition so the fine crystals have time to dissolve into the fat and liquid. A generous pinch of salt and real vanilla cut the sweetness. Butter temperature is the other lever: around 18 to 20°C (65 to 68°F) gives a smooth, stable frosting; warmer butter turns it slack and greasy.

Ingredients

• 225 g (1 cup) unsalted butter — softened to 18–20°C (65–68°F)
• 360 g (3 cups) powdered sugar — sifted
• 2–3 tbsp (30–45 ml) heavy cream — or whole milk
• 2 tsp vanilla extract
• ⅛ tsp fine salt

Method

1. Beat the softened butter alone on medium-high speed for 3 to 4 minutes, until it turns noticeably paler and looks fluffy. Scrape the bowl once halfway.
2. Turn the mixer to low and add the sifted powdered sugar about one cup at a time, letting each addition disappear before adding the next. Starting slowly keeps a sugar cloud from rising out of the bowl.
3. Add the salt, vanilla and 2 tbsp cream. Mix on low until combined, then increase to medium-high and beat for 3 to 5 minutes, until light, smooth and creamy.
4. Rub a little frosting between your fingers. If you still feel grains of sugar, beat for another 2 minutes. If it is too stiff to spread, add the remaining cream 1 tsp at a time.
5. For piping, aim for a frosting that holds a stiff peak and a sharp ridge from the tip. For spreading on a sheet cake, make it slightly softer with a touch more cream.
6. To remove air bubbles before smoothing a cake, switch to the paddle on the lowest speed for 2 minutes, or press and stir the frosting against the side of the bowl with a spatula.

Tips for success

• If you need a very white frosting, use clear vanilla and beat the butter extra long; a tiny dot of violet gel color also neutralizes the yellow tint.
• Gel food coloring gives deep shades without thinning the frosting. Colors darken as they sit, so mix them a little lighter than your target.
• On a hot day, replace 55 g (¼ cup) of the butter with high-ratio or regular vegetable shortening for a frosting that holds its shape longer.

Substitutions

Heavy cream

Whole milk works and gives a slightly lighter, less rich frosting. Water also works but makes it taste flatter.

Unsalted butter

Salted butter works; skip the added salt. Plant-based butter sticks give a softer frosting that needs chilling to pipe crisp details.

Vanilla extract

Use almond extract (only ½ tsp, it is strong), lemon zest or a tablespoon of seedless jam for a different flavor.

Variations

Chocolate American buttercream

Replace 60 g of the powdered sugar with sifted Dutch-process cocoa and add 1 extra tbsp cream.

Strawberry buttercream

Beat in 15 g (½ cup) freeze-dried strawberries ground to a powder and sifted.

Troubleshooting

Frosting tastes gritty

The sugar was not sifted or beaten long enough. Beat for several more minutes, add 1 tsp cream, and let it sit 10 minutes before beating again so the sugar dissolves.

Frosting is soft, greasy or sliding

The butter or kitchen was too warm. Chill the bowl for 15 minutes, then beat again. If it is still loose, beat in more powdered sugar a little at a time.

Frosting looks curdled

The butter was too cold or the liquid was cold. Keep beating; if it does not come together, warm the outside of the bowl briefly with a warm towel.

Storage

Keep the frosting covered at cool room temperature for up to 1 day, refrigerate for up to 1 week, or freeze for up to 3 months. Bring cold frosting to room temperature and re-beat until smooth before using. A frosted cake is fine at cool room temperature for 2 days.