I have been asked to make cookies with the following recipe.  it doesn't look like any cooked icing recipe I've seen  and the measurements are a little odd to me.   Does this sound like something that needs to be cooked?  Its a "my grandmother made it this way" recipe:

1lb powdered sugar

2Tbsp vanilla extract

2 cups whole milk

2/3 stick of butter

At first glance I thought it was an American buttercream recipe but then I saw the 2 CUPS of whole milk.  Are you sure that measurement is correct and it isn't 2 TBSP of milk?  It also seems like a lot of vanilla.

And no, an American buttercream does not get cooked.

I do know that some people put powdered sugar in their cooked flour frosting... but the ratios there seem way off and no flour or cornstarch...

Maybe it is a glaze type icing?

When I make ABC I use 2 Tablespoons flavoring.   To me it makes a HUGE difference in taste and feel all recipes would benifit from more flavoring - be it vanilla, or whatever.

I make cooked icing all the time.  Agree forjenns, these ingredients don't represent my recipe or any cooked icing recipe I've ever seen either. I think I agree with Freckles0829..it's a glaze recipe. Kinda reminds me of the proportions of my Mom's glaze she used for petite fores, and sugar cookies.