Salted Caramel Buttercream Frosting Recipe

This salted caramel buttercream frosting is whipped butter and powdered sugar beaten with a homemade salted caramel sauce. It takes about 35 minutes of hands-on time plus cooling, and one batch frosts 18 to 20 cupcakes or one 8 inch layer cake.

The one rule: the caramel has to be fully cool before it touches the butter. Warm caramel melts the butter. You get soup, not swirls. If you already have a jar of homemade caramel sauce in the fridge, let it come to room temperature and skip straight to the buttercream.

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Two Parts: The Caramel Sauce and the Butter Base

The sauce is 1 cup granulated sugar, 6 tablespoons unsalted butter, ½ cup heavy cream and 1 teaspoon sea salt. The buttercream is 1 cup (2 sticks) unsalted butter, 3½ cups sifted powdered sugar, ⅓ cup of that cooled caramel, ¼ teaspoon sea salt and 1 to 2 tablespoons of cream or milk if it needs loosening.

Have the butter and cream for the sauce at room temperature. Cold dairy hitting molten sugar makes it seize into hard lumps, and the sputtering is much fiercer. Unsalted butter in both parts lets you decide the salt yourself, since salted brands vary a lot.

Notice the numbers. The sauce makes roughly a cup, and the frosting only takes ⅓ cup. On purpose. More caramel than that and the buttercream gets too soft to pipe. The rest is yours to drizzle over the finished cupcakes.

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Cooking a Dry Caramel Without Burning It

Put the sugar in a medium saucepan over medium heat with no water and stir it with a heat-resistant spatula or a wooden spoon, though a silicone spatula is a little easier because it reaches right into the corners of the pan, where the sugar colors first.

The sugar will clump into sandy lumps before it melts. That is normal. Keep stirring. The lumps dissolve into a clear amber liquid, and you keep cooking it, still stirring, until it is the color of a copper penny and smells nutty, like toffee. Pale caramel tastes only sweet. If you see smoke or it smells sharp, it has gone too far and will taste bitter in the frosting.

Once every grain has melted, stir in the butter; it bubbles up hard, so keep your hand back and keep stirring until it blends in. Pour in the cream slowly while stirring, let the sauce boil for 1 full minute, then take it off the heat and stir in the teaspoon of sea salt. That minute of boiling is what gives the sauce enough body.

Now let it cool completely. This takes longer than the cooking, so plan on about an hour on the counter, or make the sauce the night before.

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Beating the Caramel Into the Butter

Beat the room temperature butter on medium speed for about 3 minutes, until it looks paler and fluffy. That air is what keeps the frosting light once the sugar goes in.

Add the sifted powdered sugar one cup at a time, starting on low so it does not fly out of the bowl, then turning up to medium. Then add ⅓ cup cooled caramel and the ¼ teaspoon salt and beat until smooth. It turns tan fast.

Too stiff? Add cream or milk a tablespoon at a time. Then whip on medium-high for 2 to 3 minutes so it turns light and airy. Do a spoon test. Drag a spoon through and lift it. The frosting should curl over at the tip and keep its ridges. If it droops, it is too soft; if it cracks, it needs a splash more cream.

Taste before you call it done. Caramels vary, and some need another pinch of salt to stop the frosting tasting flat. For a stronger caramel flavor, beat in another tablespoon or two of the cooled sauce and check that it still holds a peak. If it slumps, a few spoonfuls of powdered sugar bring it back.

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When Caramel Frosting Turns Soupy, Curdled or Grainy

• Soupy or sliding off the spoon: the caramel was still warm or the kitchen is hot. Chill the whole bowl for 15 to 20 minutes, then beat again, and hold off on adding a pile of extra sugar first, because cold fixes this far more often than sugar does and too much sugar only makes it sweet and stiff.
• Curdled, with little lumps of butter: the butter was too cold when the caramel went in. Warm the outside of the bowl with a hot towel for a few seconds and keep beating until it turns smooth.
• Greasy and shiny: the butter got too warm from over-beating. Ten minutes in the fridge and a short rebeat sorts it out.
• Grainy: the powdered sugar was not sifted, or a few sugar crystals were left in the caramel. Sift next time; for now, beat 2 more minutes and add a tablespoon of cream.
• Bitter: the caramel went past copper into dark brown. There is no saving that batch of sauce, so start the caramel again.

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Caramel Buttercream vs Old-Fashioned Cooked Caramel Icing

These are two different frostings. This one is an American-style buttercream flavored with caramel sauce, so it stays soft, fluffy and pipeable, and it tastes of butter and toffee with a salty edge.

Old-fashioned caramel icing, the kind poured over Southern caramel cake, is cooked brown sugar, butter and milk beaten until it thickens. It sets with a fudgy, sugary crust and you spread it fast while it is warm. If that is what you are after, my brown sugar frosting is the closer match. For piping swirls on cupcakes, stay with this buttercream.

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How Far One Batch Goes

One batch covers 18 to 20 cupcakes with a generous swirl, or fills and frosts one 8 inch layer cake. It holds a star tip well, especially after 15 minutes in the fridge before piping. Try it on caramel cupcakes, salted caramel apple cupcakes or rich chocolate cupcakes.

For a layer cake, it is the frosting I would put on a salted caramel cake. A plain vanilla buttercream uses the same butter and sugar method, and a chocolate buttercream works next to it if you want two flavors on one tray.

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Making It Ahead and Using the Leftover Caramel

The frosting keeps in an airtight container in the fridge for up to 5 days. Let it soften at room temperature, then rewhip for 1 to 2 minutes until it is fluffy again. It also freezes for up to a month; thaw it overnight in the fridge, bring it to room temperature and rewhip.

If you are frosting the next day, the frosting can stay covered at cool room temperature overnight instead of going in the fridge. Spare caramel sauce keeps in a jar in the fridge for about 2 weeks, and a warmed spoonful drizzled over the frosted cupcakes, a slice of cake or a bowl of vanilla ice cream is the easiest way to use it up.

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Salted Caramel Frosting Questions

Can I use store-bought caramel sauce?

Yes. Use ⅓ cup of a thick caramel sauce at room temperature, and taste before adding the extra salt. Thin, syrupy sauces and ones with added thickeners make the frosting soft or gummy.

Can I use salted butter instead of unsalted?

You can, but leave out the ¼ teaspoon salt in the buttercream and taste at the end. Salted butter varies by brand, so the frosting can easily end up too salty.

Does salted caramel buttercream need to be refrigerated?

A frosted cake or cupcakes can sit at cool room temperature for a day. For longer, refrigerate them and let them stand out for about 30 minutes before serving so the frosting softens.