My Classic Lemon Ermine Frosting recipe is bright, fluffy, and loaded with lemon flavor that you cannot resist.
In a medium saucepan whisk the milk, sugar, and flour until smooth and then place over medium-low heat.
Heat and whisk constantly until the mixture comes to a boil.
Continue cooking and whisking for about just one or two more minutes, until the mixture thickens but not browned.
Pour the mixture through a sieve and into a medium bowl. Place some plastic wrap over the surface of the mixture and let cool completely to room temperature (about 1 hour).
Place the milk mixture in the bowl of a stand mixer fitted with a whisk attachment (or use a handheld electric mixer) and whisk on medium speed.
Gradually add in the softened butter, a few slices at a time, until fully incorporated.