Ermine frosting, also known as boiled milk frosting or flour frosting, is a silky, lightly sweetened frosting that's cooked on the stovetop. Its mild, buttery flavor is the perfect finishing touch for your next batch of cupcakes.
Ermine frosting goes by many names, including boiled milk frosting, roux frosting, cooked frosting, and flour frosting. While it takes more effort to prepare than a classic American buttercream frosting, it is significantly less sweet.
Ermine frosting is silky smooth and tastes buttery, with a mild vanilla flavor. While the recipe includes flour, the finished frosting does not taste at all like flour. It's the perfect frosting for those who think buttercream frosting is too sweet.
Ingredients and substitutions
- All-purpose flour - Flour is necessary to thicken your frosting base and add structure to your finished frosting.
- Granulated sugar - ¾ cup of granulated sugar adds a light amount of sweetness to your frosting. Another ¼ cup of sugar can be added to create a slightly sweeter frosting (the recipe is lightly sweetened as written).
- Salt - Enhances the flavor of your frosting without making it "salty".
- Whole milk - Milk is cooked along with the flour and sugar to make your frosting base. Whole milk is best because it makes your frosting rich and creamy. To make a whole milk substitute with skim milk and heavy cream, add 1.5 tablespoons of heavy cream to a measuring cup, then fill to the 1 cup line with skim milk.
- Unsalted butter - High quality, unsalted butter is best for making a silky, flavorful ermine frosting. If using salted butter, the listed salt can be omitted from the recipe.
- Vanilla extract - Adds depth of flavor to your frosting. Vanilla can be substituted with other extracts to make unique frosting flavors. Peppermint or almond extract can be substituted in at half the amount (their flavors are significantly stronger).
Tips and tricks
Ermine frosting can be a bit tricky if you've never made a cooked frosting before. Once you get the hang of it, you'll never go back to traditional buttercream!
Use a whisk - Continue whisking your flour and milk mixture together until no lumps remain. You won't get a smooth pudding base without a whisk.
Cook until thickened - Your "roux" or pudding base must be cooked until it thickens significantly. The mixture starts out looking essentially like milk, but is ready to come off the heat after it has thickened to a sweetened condensed milk or Elmer's glue consistency (and it will continue to thicken even more as it cools).
The importance of the pudding base - The purpose of thickening the pudding mixture is to 1) cook the flour, which makes it safe to eat and removes the "raw flour" taste, and to 2) cook out excess moisture, which stabilizes your finished frosting. If your pudding base isn't thickened enough, your frosting will turn out thin.
Lumpy pudding base? - If your pudding base contains lumps after whisking and cooking, push through a fine mesh sieve before cooling.
Cool the pudding base completely - Arguably the most important step - make sure your pudding base is cooled completely to room temperature before adding it to the whipped butter. If the pudding mixture is even a little warm, it will melt the butter and turn into a thin, oily mess.
Cooling alternatives - After covering your bowl, allow it to set at room temperature for 1 to 1.5 hours. To speed up cooling, transfer the pudding mixture to the refrigerator, but don't allow it to go below room temperature. Otherwise, the mixture will thicken too much and become difficult to work with.
Add pudding mixture slowly - Slowly add your pudding mixture to the butter mixture, one tablespoon at a time, until it's all incorporated. Otherwise, the butter base can break.
Frequently asked questions
Ermine frosting gets its name from the ermine, a species of weasel with silky, soft white fur.
Leftover ermine frosting can be stored in the refrigerator for up to 1 week, or in the freezer for up to 3 months. After bringing to room temperature, rewhip before piping.
Baked goods frosted with ermine frosting can be stored at room temperature for up to six hours after preparing. Otherwise, baked goods should be stored in the refrigerator.
Ermine frosting, made mainly of butter, will melt around 90 to 95 degrees Fahrenheit. If you live in a humid or tropical environment, I recommend storing frosted baked goods in the refrigerator until 30 minutes before serving. Do not display frosted cakes in direct sunlight or outdoors in hot weather - they will melt.
No, ermine frosting does not crust like traditional buttercream frosting. The reason buttercream frosting crusts is due to the large quantity of sugar added to the frosting. Since ermine frosting is significantly less sweet, it does not contain enough sugar to form a crust after piping.
Ermine frosting makes a great alternative for buttercream frosting if you're looking for a less sweet frosting.
While the main ingredient of both frostings is butter, ermine frosting utilizes a "roux" of sorts to add stability. This "roux", or pudding base, is made with flour, granulated sugar, and whole milk. Buttercream relies on large amounts of confectioner's sugar alone for thickening, which is why it's so sweet.
Buttercream frosting is significantly easier to prepare, taking only five minutes (or less) to whip together in a single bowl.
The pudding base of your ermine frosting must first be cooked on the stovetop, then cooled completely. Last, it's whipped into room temperature butter to create your finished frosting. The entire process can take up to 1.5 hours from beginning to end and requires extra care and effort throughout the process.
- ¾ cup (149 g) granulated sugar
- ¼ cup (30 g) all-purpose flour
- ½ teaspoon salt
- 1 cup (240 g) whole milk
- 1 cup (226 g) unsalted butter, room temperature
- 2 teaspoons vanilla extract
- In a saucepan over medium heat, add sugar, flour, and salt. Whisk in milk and continue whisking until smooth.
- Cook over medium heat for about 5 to 7 minutes, whisking frequently, until mixture looks very thick (like sweetened condensed milk consistency). Remove from heat.
- Transfer mixture to a bowl. Press plastic wrap over the top of the mixture and up the sides of the bowl to prevent a skin from forming. Allow mixture to cool completely to room temperature, about an hour. (To speed up cooling, transfer to the refrigerator, but don't allow it to go below room temperature. Mixture will solidify and become difficult to work with.)
- Once flour mixture has cooled, add room temperature butter to a large bowl and beat with a hand mixer (or a stand mixer) until light and fluffy, about 2 to 3 minutes.
- Add your cooled flour mixture, 1 tablespoon at a time, to the whipped butter and beat until smooth, scraping the sides of the bowl frequently. Continue until all of your flour mixture has been incorporated. (If your flour mixture is even a little warm it will melt the butter and ruin the frosting. Flour mixture must be room temperature, not warm, for this step).
- Add vanilla extract and mix to combine. Frosting should be silky smooth with a whipped texture.
- Pipe or spread frosting with a knife onto cupcakes and serve.
- Recipe makes about 2.5 cups of frosting - enough to frost 15 cupcakes, a 6-inch round layer cake, or a thin coating on a 9x13 cake. Recipe can easily be doubled or tripled.
- Ermine frosting melts at high temperatures, around 90 to 95 degrees Fahrenheit. If you live in a tropical/humid environment, I suggest storing frosted cake/cupcakes in the refrigerator.
- Ermine frosted baked goods can be stored at room temperature for up to six hours after frosting, and otherwise need to be stored in the refrigerator. Frosting will keep for up to 1 week in the refrigerator or 3 months in the freezer.
- Food coloring can be added in along with vanilla extract if desired.
- Vanilla extract can be substituted with half the amount of peppermint or almond extract.