...
>I would very much like to be able to make cookies like this, but they
>call for butter.

You can't make the frosting/icing with oils - you need the "body" of a
butter or margarine. You can substitute oils, however, in the cooked part -
and it's healthier for you.

Have you tried any of the Kosher/Pareve margarines, such as Mazola Extra
Light or Fleischman's Light stick margarine or Country Crock Corn oil
margarine? The mazola and the Country Crock have enough body to stand up in
frostings. The Fleischman's says it's not for cooking.

Mark