Buttercream Roux Frosting

I never seem to get the standard butter/powdered sugar buttercream right, and I really don’t like the too sweet taste or the heavy texture, so yesterday I went searching for a new method. I learned about buttercream roux, traditionally used on Red Velvet cakes. I think I will be using this cooked frosting for a while; it is soft and fluffy and not too sweet. Even though is it a bit more effort than whipping together butter and powdered sugar the result is worth the extra pan to wash.
I would like to try it with soy milk instead of cow’s milk, but of course that will change the texture and flavor – perhaps in a good way, certainly in a more healthy way. I am sure other flavourings could be substituted for the vanilla and I wonder if you melted chocolate into the roux if that would work. I foresee many cake experiments in my future.
Buttercream Roux Frosting
covers a two layer cake
1/2 cup milk
2 -3 Tbsp flour
1/2 cup butter, room temperature
1/2 cup granulated sugar
vanilla to taste
Heat the milk and flour until it thickens, stirring vigorously. Remove from heat , pour into a shallow bowl and allow to cool completely. Cream butter and sugar until light. Check the roux for lumps; strain if necessary. Add in the cooled roux and beat until creamy and fluffy. It is possible to do this with a whisk but an electric beater is certainly less effort.