Ermine frosting, also known as boiled milk frosting, is a cooked flour and milk paste whipped into butter and granulated sugar until it turns smooth and fluffy. It takes about 47 minutes, and 30 of those are just waiting for the paste to cool. One batch frosts 12 cupcakes or one 8 inch layer cake.
It tastes like something between whipped cream and buttercream, and it is far less sweet than American buttercream. It still pipes clean swirls and keeps its shape on a warm day. The one rule: the paste has to be completely cold before it meets the butter.
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- The paste: 5 tablespoons all-purpose flour whisked into 1 cup whole milk, cooked 5 to 7 minutes
- The base: 1 cup softened unsalted butter beaten with 1 cup granulated sugar for about 5 minutes
- Flavor: 1 tablespoon vanilla extract and a pinch of salt
- Time: 10 minutes prep, 7 minutes on the stove, 30 minutes cooling, about 47 minutes in all
- Covers: 12 cupcakes or one 8 inch layer cake
- Keeps: up to 3 days covered in the fridge; re-whip before using
Why It Is Also Called Boiled Milk or Cooked Flour Frosting
All three names describe the same thing. Milk and flour are cooked into a thick pudding, sometimes called a roux even though there is no fat in the pan, and that paste does the work powdered sugar does in a quick buttercream. Older recipe cards call it boiled milk icing, flour buttercream, or simply milk frosting.
It is the old style frosting for red velvet cake, from before cream cheese frosting took over. It reminds me of the kind of frosting my grandmother used, back when butter was softened on the windowsill and everything was whisked by hand.
You need flour, milk, butter, sugar, vanilla, and salt. I’ve tested this with both whole milk and 2%. Whole milk gives a smoother, richer result.
Cooking the Milk Paste Until It Mounds
Whisk the flour into the cold milk in a small saucepan until completely smooth before you turn on the heat. If you start with lumps, they follow you through the entire batch. Set the pan over medium heat and keep the whisk moving. In 5 to 7 minutes the milk goes from thin, to slightly thick, to a pudding that no longer runs from the spoon but mounds gently. Thick, but still glossy.
Scrape it into a shallow bowl and press plastic wrap right onto the surface so no skin forms. Cool it at room temperature or in the fridge for about 30 minutes. If a few lumps slipped through, push the warm paste through a fine sieve first.
Before it goes anywhere near the butter, touch the middle of the bowl. It should feel cool all the way through, close to the temperature of the soft butter. If it is even slightly warm, the frosting can split. I’ve tried shortcuts. They do not work.
Granulated Sugar, No Powdered Sugar Needed
This is a frosting without powdered sugar. Beat the softened butter and the granulated sugar on medium high speed for about 5 minutes, until pale and fluffy. The butter should take a fingerprint easily but not look shiny or greasy. If it is too hard, set it on a warm plate for 20 minutes while the paste cools.
Some graininess will still be there after 5 minutes. That is fine. The wet paste keeps dissolving the sugar as you beat it in. I’ve seen bakers swap in powdered sugar, thinking it might dissolve faster. It does not help. Powdered sugar adds cornstarch and much more sweetness, and the frosting loses the light, not too sweet taste that is the whole point of ermine.
Beating In the Cold Paste a Spoonful at a Time
Add the cooled paste to the butter mixture one tablespoon at a time, beating well after each addition. Go slow. Partway through, the frosting can look loose or a little curdled before it tightens. Keep going.
By the last spoonful it should look smooth, slightly glossy, and firm enough to pipe. Not dense, but not runny either. Add the vanilla and the pinch of salt and beat just until blended. The salt balances the sugar and brings the butter flavor forward. I usually pipe a test swirl on parchment: it should hold its ridges and still spread smoothly with an offset spatula.
Split, Soupy, or Grainy Ermine and How to Rescue It
- Looks curdled, with little lumps of butter: the butter or the paste was too cold. Warm the outside of the bowl with a warm towel for a few seconds and keep beating until it comes together.
- Soupy or sliding off the whisk: something was warm, usually the paste. Chill the whole bowl for 10 to 15 minutes, then beat again on medium high.
- Gritty on the tongue: the butter and sugar needed longer. Keep beating for a few more minutes; the moisture in the paste dissolves the crystals.
- Small white specks: lumps from the paste. Next time whisk the flour into cold milk and sieve the paste before cooling.
- Too soft to pipe on a warm day: chill the frosting for 10 minutes, or chill the piped cupcakes briefly to set the swirls.
Ermine vs American Buttercream vs Cool Whip Frosting
Ermine has more structure than whipped frostings and a clean vanilla flavor. It is much less sweet than American buttercream, which is mostly powdered sugar and butter, and it feels lighter on the tongue. American buttercream crusts and is quicker to make, with no cooking or cooling.
The Cool Whip cream cheese frosting is lighter, tangier, and much softer. It is great for quick cakes or no-bake desserts, but it has to stay cold. Whipped cream frosting is close to ermine in lightness, though it lacks the structure. If I am frosting a wedding style vanilla cake or red velvet, I go with ermine. If I am doing a tray of sugar cookie bars, I reach for the Cool Whip version.
For a frosting that skips the paste entirely, my vanilla buttercream frosting uses the direct method. For another cooked style, 7 minute frosting is made with egg whites instead of flour.
Red Velvet, Layer Cakes, and Piped Roses
Ermine slices cleanly through layer cakes without dragging and holds swirls on cupcakes. Try it on red velvet cupcakes or a moist vanilla cake, where balance matters more than sugar.
It makes a dependable cake filling too. Spread it between layers, chill the cake slightly, then crumb coat for a clean finish. I’ve even used ermine as a base for piping roses. It holds up better than you would expect for something so smooth.
Flavored extracts work well. Maple extract adds a warm edge for fall bakes, and my maple frosting is a good next step once you have ermine down.
Fridge, Freezer, and Re-Whipping
Ermine is at its best the day it is made. To store it, cover it and keep it in the fridge for up to 3 days. It firms up like cold butter, so let it come back to room temperature and re-whip it for a minute before spreading.
It can be frozen, too. Pack it into an airtight container, freeze for up to 1 month, thaw overnight in the fridge, then bring it to room temperature and beat until smooth again. A frosted cake should go in the fridge overnight; take it out about 30 minutes before slicing so the frosting softens.
Boiled Milk Frosting Questions
Can I make ermine frosting with cornstarch instead of flour?
Yes. Cornstarch thickens about twice as strongly as flour, so use about 2½ tablespoons in place of the 5 tablespoons flour and cook it the same way. The paste sets a little firmer and glossier.
Is there a gluten free ermine frosting?
Use the cornstarch version above, or a 1 to 1 gluten free flour blend in the same 5 tablespoon amount. Everything else in the recipe is naturally gluten free; check your vanilla label.
Can I use brown sugar in ermine frosting?
You can swap some or all of the granulated sugar for light brown sugar. The frosting turns tan and tastes like caramel, and it needs a little extra beating to dissolve. For a dedicated version, see my brown sugar frosting.
Why does ermine frosting taste like butter?
With so little sugar, the butter is the main flavor. Use good unsalted butter, do not skip the pinch of salt, and use the full tablespoon of vanilla.
Ermine Frosting (Boiled Milk Frosting)
This ermine frosting, also called boiled milk frosting or ermine buttercream, is a light, less sweet frosting made with a cooked flour and milk paste, butter, granulated sugar, and vanilla, with no powdered sugar. It takes about 47 minutes, most of it cooling time, and frosts 12 cupcakes or one 8 inch layer cake with a smooth, fluffy, pipeable finish. The paste must be completely cool before it is beaten into the creamed butter and sugar one spoonful at a time, or the frosting splits. Use it on red velvet cake, vanilla layer cakes, cupcakes, piped roses, and as a filling between cake layers. Keep it covered in the fridge for up to 3 days or freeze it for 1 month, and re-whip before using.
Ingredients
- 5 tablespoons all-purpose flour
- 1 cup whole milk
- 1 cup unsalted butter, softened
- 1 cup granulated sugar
- 1 tablespoon vanilla extract
- Pinch of salt
Instructions
- MAKE THE ROUX: In a small saucepan, whisk together the flour and milk until completely smooth. Place over medium heat and cook, whisking constantly, for 5 to 7 minutes or until the mixture thickens to a pudding-like consistency.
- COOL THE ROUX: Remove the thickened mixture from heat. Transfer to a shallow bowl and cover the surface directly with plastic wrap to prevent a skin from forming. Let it cool completely at room temperature or in the refrigerator for about 30 minutes.
- BEAT THE BUTTER AND SUGAR: In a stand mixer fitted with a paddle attachment or using a handheld mixer, beat the softened butter and granulated sugar together on medium-high speed for about 5 minutes or until light and fluffy. The sugar should start to dissolve, though some graininess is normal at this stage.
- ADD THE ROUX TO THE BUTTER MIXTURE: Add the cooled roux to the butter mixture one tablespoon at a time, beating well after each addition. Continue until all the roux is incorporated and the mixture looks light and airy.
- FINISH THE FROSTING: Add the vanilla extract and a pinch of salt. Beat again just until fully blended. The finished frosting should appear smooth, glossy, and hold its shape when piped.
Notes
Whisk the flour into cold milk before heating so the paste stays smooth; sieve it if any lumps form. The paste must be completely cool, close to the temperature of the soft butter, before adding it, or the frosting may separate. If it looks curdled, the mixture is too cold: warm the bowl sides briefly and keep beating. If it is soupy, chill it for 10 to 15 minutes and beat again. Use granulated sugar, not powdered. This frosting is best used the day it is made but can be stored in the refrigerator for up to 3 days or frozen for up to 1 month. Bring to room temperature and re-whip before using.
Nutrition Information
Yield
12Serving Size
1Amount Per Serving Calories 228Total Fat 16gSaturated Fat 9.9gTrans Fat 0.0gUnsaturated Fat 5.2gCholesterol 43mgSodium 22mgCarbohydrates 20gFiber 0.1gSugar 18gProtein 1.2g
