It's not uncommon for this frosting to end up a little grainy. I've not figured out the fool-proof method to prevent it. This used to be made with oleo, which is too watery now, but probably acted differently with the sugar.
Ingredients
Milk: 1 Cup
Butter: 1 Cup
Flour: 3 TSP
Granulated Sugar: 1 Cup
Vanilla: 1 TSP
Instructions
Cook flour and milk in a saucepan over medium heat, until very thick. Stir constantly to prevent burning.
Cream butter, sugar, and vanilla until very fluffy, the consistency of whipped cream.
Add creamed mixture to cooled cooked mixture. Don't let the first mixture get completely cold because it's harder to mix.
NOTE: This frosting, as wonderful as it is once on the cake and refrigerated, can be a little grainy. This is because it was once made with oleo/margarine. There is too much water in the margarine these days, so butter it is. But creaming butter and sugar coats the sugar grains with butter fat, keeping it from dissolving since it's never cooked after creaming (like cookies). It's still wicked good though!
Open this recipe in Recipe Gadget to save, organize, and cook it.