Recipe video above. This is actually an old fashioned frosting called Ermine Frosting that was traditionally used for Red Velvet Cake. Though not widely known, many consider it far superior to buttercream because its 100% silky smooth, far less sweet and much fluffier - which means you can pipe sky high mounds onto cupcakes and it won't be sickly sweet. The texture is like whipped cream but slightly more dense. But while whipped cream deflates within hours, this frosting will hold its shape for days! Don't be turned off by the flour - you absolutely cannot taste it at all. Makes enough to frost 12 cupcakes generously with tall swirls (pictured), or 24 cupcakes swirled on with a knife, or a two or three layer 20 - 23cm/8-9" cake.
Place flour and sugar in a large saucepan over medium heat. Cook, stirring constantly, for 30 seconds.
While whisking constantly, slowly pour the milk in (this ensure it's lump free).
As the milk gets hotter, it will start to thicken - stir constantly so the base doesn't catch.
Cook until the mixture thickens in a thick, dolloping custard - see video for texture. TIP: Thicker texture = thicker frosting texture but won't make the frosting dense, it's still fluffy and spreadable but it just makes it "sturdier" with sharper edges when piped.
Remove from heat and scrape into a bowl. Cover with cling wrap, pressing down onto the surface to prevent a skin from forming.
Cool completely (I leave on counter for 20 min or so then refrigerate 30 min to speed up but don't let it get chilled, best at room temp to beat into butter). You can leave in fridge overnight but take it out 1 hour prior to using (to dechill - otherwise it won't mix well with softened butter).
Making the Fluffy Frosting:
Place butter in a bowl and use either a handheld beater or stand mixer (with whisk attachment) to beat for 3 minutes until it's smooth and changes from yellow to very pale yellow, almost white.
Now start whipping in the Thickening Roux. On speed 5 (medium), start adding the thick roux one heaped tablespoon at a time. Take about 1 minute to add it all.
Once all added, add vanilla and salt, then whip for 2 to 3 minutes until you can see that it is still enough to hold peaks. Then it's ready to use!
Chocolate flavoured option:
Beat in the cocoa powder at the end, just until mixed through.
Frosting cakes and cupcakes:
Use it like any other frosting on cakes and cupcakes - either spread it on with a knife or put in a piping bag. You can pipe sky-high mounds and it will hold its form, as pictured on Vanilla Cupcakes in this post.
See notes for storage / make ahead.
1. Sugar - caster/superfine ok too. 1 cup sugar yields a sweet frosting but not overly sweet like buttercream which uses about 2.5 - 3 cups equivalent. Can reduce to as little as 1/2 cup - then this really does taste like a lightly sweetened whipped cream! 2. Whiteness - it will depend on the colour of your butter. Economical butter tends to be more yellow so the frosting will have an off white colour. European butters (such as Lurpak) are paler so the frosting will be closer to white. The butter whipping stage will lighten the colour of the butter.Whitening - if you really want pure white, you can purchase a frosting whitener like this one from Wilton and also get clear imitation vanilla essence but the flavour isn't as good and pure as vanilla extract.The other trick is to add tiny drops of blue or purple into the frosting. These colours are opposite yellow on the colour wheel so they will offset the yellow tinge. For liquid colouring, use a tiny drop at a time. For gel (more intense), dip a toothpick in and wipe onto the frosting surface.Frosting can also be tinted - it's like a really fluffy buttercream, so anything you can do to colour / flavour buttercream, you can do with this frosting!3. Softened Butter - this is butter that is at 17°C/63°F, which is cooler than you might expect! It should be soft enough that it is pliable so when you poke it, it leaves an indent. But still cool enough so that you don't end up with shiny grease your your finger.If your butter gets too soft, the frosting will be too sloppy, the same problem you'd run into with any butter based frosting like buttercream frosting.4. Storage & make ahead:
This frosting is best used straight after making.
On cooler days (22C/71F or so), frosted cakes, cupcakes etc can stay out on the counter.
On warmer days, it will need to be refrigerated - the butter is what will make the frosting droop. Take out of fridge 1 - 1.5 hrs before serving to bring so the frosting can soften (it firms up in the fridge due to the butter).
The flour milk roux can be made the day before and refrigerated overnight, but then take it out of the fridge 1 hour prior to take the chill out of it, you want it at room temperature.
Freezing - up to 3 months, thaw overnight in the fridge
5. Recipe source: I cannot remember where I first obtained this recipe (it was over 10 years ago) but I cross checked my usual recipe resources before publishing it and this recipe uses the same quantities as the New York Times Ermine Frosting, but a slightly different method. (Note: that's a paid resource though you can view limited pages for free)6. Nutrition assuming 12 servings (as pictured in post - tall swirls!). Frosting only.