Sour Cream Frosting Recipe

This sour cream frosting is a soft, tangy butter frosting made with 1 cup of full-fat sour cream, 1/2 cup of softened butter, 3 to 4 cups of powdered sugar, and vanilla. It takes about 10 minutes, needs no cooking, and frosts one 8 inch two layer cake or 18 to 24 cupcakes.

The sugar decides the texture. With 3 cups you get a spreadable, almost cloud-like frosting for sheet cakes and cookies. Four cups makes it firm enough to pipe soft swirls. Either way it is less sweet and lighter on the tongue than vanilla buttercream, with a clean dairy tang that sits well on chocolate cake.

What Goes Into the Bowl

• Ratio: 2 parts sour cream to 1 part butter by volume (1 cup to 1/2 cup), plus 3 to 4 cups sifted powdered sugar
• Flavor: 1 1/2 teaspoons pure vanilla and an optional pinch of salt
• Time: 10 minutes, no cooking
• Yield: one 8 inch two layer cake or 18 to 24 cupcakes
• Spread or pipe: 3 cups sugar spreads; 4 cups plus 10 minutes in the fridge pipes
• Keeps: 3 days covered in the fridge; it does not freeze well

Full-Fat Sour Cream and Cool, Soft Butter

Use full-fat sour cream. Light and fat-free versions carry more water and less fat, and the frosting turns soupy no matter how much sugar you pile in. Before measuring, pour off any clear liquid sitting on top of the tub instead of stirring it back in. That little bit of whey is enough to loosen the whole bowl. Making your own? My homemade sour cream works once it has fully thickened in the fridge.

The butter should dent when you press it but still feel cool, which usually means about 30 minutes out of the fridge. Beat it with the vanilla on medium speed for about 2 minutes, until it turns pale and creamy like the bowl above. That beaten butter is the only structure this frosting has, so give it the full 2 minutes. Butter that is too cold leaves lumps. Butter that is greasy and starting to melt gives you a frosting that slides off the cake.

Pure vanilla is worth it here, because there is very little else in the bowl for an imitation flavor to hide behind.

Why It Looks Curdled, and When to Stop Beating

Add the sour cream all at once and mix until it is worked in. For a moment the bowl will look split and grainy. Don’t panic. Cold, watery sour cream is meeting fat, and it smooths out as soon as the powdered sugar goes in.

Sift the sugar and add it one cup at a time, mixing well after each. At 3 cups, stop and check: a spoonful should hold a soft peak whose tip curls over. Need it firmer for piping? Add the fourth cup. Taste before reaching for salt. A pinch takes the edge off the sweetness, and you may not need it at all. Fold in any zest or cocoa now.

Then stop. Sour cream thins the longer it is beaten, so a frosting that looked right can go loose after a few more minutes of mixing. Smooth and holding a soft peak means done.

Rescuing Soft or Runny Sour Cream Frosting

• Runny from the start: light sour cream, or the whey went in. Beat in more sifted powdered sugar a tablespoon at a time, then chill for 15 minutes.
• Soft after sitting out: the butter warmed up. Chill the bowl for 10 to 15 minutes and stir it by hand rather than whipping it again.
• Lumpy or broken: the butter was too cold. Let the bowl sit for 5 minutes, then beat again briefly.
• Too thick to spread: stir in 1 teaspoon of milk or cream.
• Too sweet: add a pinch of salt, or fold in one more spoonful of sour cream by hand.

Can You Make Sour Cream Frosting Without Butter?

Not this one. The butter is what lets it hold a swirl; sour cream and powdered sugar on their own stay pourable. That pair does make a good sour cream glaze, though. Whisk about 3 tablespoons of sour cream into 1 cup of sifted powdered sugar with a drop of vanilla. Add more sour cream a teaspoon at a time until it falls off the whisk in a thick ribbon, then spoon it over a pound cake, a bundt, or sour cream blueberry muffins. It needs the fridge, just like the frosting.

If you want a tangy frosting with more body, my easy cream cheese frosting is the sturdier choice. For something even lighter, try whipped cream frosting.

Cakes and Cupcakes That Suit the Tang

This frosting is at its best against something rich or chocolatey. Spread it thick on sour cream chocolate cake, or on a yellow layer cake like the one in the photos. On cupcakes, use the softer 3 cup version and swirl it on with the back of a spoon. Spooned over soft sugar cookies, it sets to a soft top rather than a crust.

Because it stays soft, skip it for tall stacked cakes or anything that sits on a warm table for hours. Think two layer cake from the fridge, not wedding tier.

Lemon, Chocolate, Almond, and Maple Versions

• Lemon or orange: fold in the zest of 1 fruit at the end. Lemon is lovely on lemon cupcakes.
• Chocolate: sift in 1 to 2 tablespoons of cocoa powder. One gives a pale mocha color and a gentle chocolate note; two tastes clearly of chocolate.
• Almond: add 1/4 teaspoon of almond extract for almond cookies or shortbread.
• Maple: swap the vanilla for maple extract on apple muffins or pumpkin spice cake.

Fridge Rules for Sour Cream Frosting

Treat it like the dairy it is. Keep the frosting covered in the fridge for up to 3 days. Let it soften for 15 to 20 minutes, then re-whip for about 30 seconds before using. Freezing is not worth it, since the texture turns grainy and weepy as it thaws.

A frosted cake goes in the fridge too, loosely covered. Take it out about 30 minutes before serving so the frosting softens, and keep it at room temperature no longer than 2 hours. That is the standard rule for perishable dairy foods, and on a hot day the window is shorter.

Pin this to your frosting board for the next chocolate cake, and tell me in the comments what you spread it on.