This Is the Easiest Last-Minute Cake Frosting You'll Ever Make
If you love cake (and really, who doesn't?), you might have already gone down the rabbit hole of making your own buttercream frosting. And what a world of sweet delight: from standard dense American style (whipped butter with powdered sugar and flavorings) to cooked syrup or meringue-based styles like Swiss, Italian, and French, or even German styles enriched with custard.
But you've never worked with a buttercream as simple as Russian.
Why Russian Buttercream is the easiest buttercream frosting
Russian buttercream does not require any fussy candy thermometer sugar work, or other fancy-pants technique. Russian buttercream is just two ingredients: butter and sweetened condensed milk. A totally pantry friendly recipe, and ideal for last-minute frosting needs! This buttercream is a wonderful back-pocket recipe, since it is so simple, perfect for when you are in a vacation rental and the kids want cupcakes and you want something better than canned frosting, but not a giant kitchen project.
How to make Russian Buttercream
All you need for Russian Buttercream is two sticks of unsalted butter and a 14-ounce can of sweetened condensed milk. The butter needs to be at cool room temperature—about an hour out of the fridge will do it—it should be easy to press your finger into it, but not be soft or shiny. If you let your butter soften too much just pop it back into the fridge and test again every 10 minutes. You want your butter and sweetened condensed milk at around the same temperature.
To make, you only need a little patience because that's the key to keeping this frosting from breaking/splitting and getting that icky curdled texture.
1. Using the whisk attachment, whip the butter until it is light and fluffy and nearly white in color. This will likely take about 5-8 minutes on medium-high speed. (I usually add a pinch of fine sea salt at this stage, and sometimes a teaspoon of vanilla paste, but it is not necessary).
2. Reduce speed to medium, and slowly drizzle in the sweetened condensed milk in a steady thin steam, aiming for the space between the bowl and the whisk. Err on the side of slow to prevent splitting. When all the sweetened condensed milk has been added, stop the mixer, scrape down the sides and bottom where it can sometimes pool, and whip again until fluffy.
3. If your frosting separates, your butter might be too warm; just pop the whole bowl in the fridge for 10-15 minutes, then re-whip.
You can add colors to this frosting: I prefer gel or powdered food color to prevent adding liquid, or you can sub a flavoring extract for the vanilla. You can also make a caramel version of this frosting using a can of dulce de leche instead of the sweetened condensed milk.
A note on serving: Cakes with this style of buttercream should be stored in the fridge until about 30 minutes to 1 hour before you want to serve.