Top-ranked recipe named "Basic Granulated Sugar Icing"
Heat milk and flour over low heat, until very thick. Let cool and set aside.
Cream together sugar and butter
(Alternatively use 1/4 cup butter and 1/4 cup shortening, and cream all three together)
Add cooled milk and flour mixture, mix thoroughly until whip cream consistency
Add vanilla, and mix thoroughly
The result is VERY sweet, but works when you have no confectioners sugar. Should have no crunchiness or gritty/grainy feeling.