Because I only had 6 ounces of trans-fat free margarine, I made 1/2 of the recipe. It was enough to frost a single 8″ round cake, cut in three layers (baked in a 3″ deep pan, with a half recipe of Zoe’s Devil’s Food Cake batter, using 2 eggs instead of 1 1/2 eggs).
Even though I was short a couple of ounces of margarine for the half recipe (and even though I was using margarine instead of butter), the recipe came out great. I added the margarine very very slowly, in little dabs, and the frosting never broke. It never looked “soupy or curdled.” I was smooth from beginning to end. I used a large egg and a large yolk and it was completely fine.