Step One: Prepare your ingredients
I get everything ready while the water in the double boiler is heating. Once you've started mixing things you can't stop mixing or you risk burning the icing, so it's best to have it all ready to go at once. DO NOT ADD THE VANILLA YET. I mix the two egg whites, water, and corn syrup in one bowl, and the sugar and cream of tartar in another. You should know that I'm exceptional at separating egg whites from the yolk. There's some cool way to do it with a water bottle but I feel more badass when I do it with just my two hands. Ok, so you have everything ready and it should look like this. Also, take the top off the vanilla extract. You can either add an actual teaspoon or you can just add a few drops straight from the bottle, it's up to you.
Step Three: Keep mixing and call yourself Sir Mixx A Lot if you're feeling corny.
You should definitely put colored sprinkles on top to add some color. I usually do pink sprinkles but my aunt likes red more than pink and it was her birthday so I sacrificed my own desire for what I thought she would like.
Things you should know:
This icing is STICKY. Really sticky. So try not to get it everywhere. And if you get it on your clothes, wash it off immediately.
Don't eat too much plain icing or you will get sick. It will be delicious, but you will get sick.
This icing is not healthy in any way, shape, or form. IT IS CORN SYRUP AND REFINED SUGAR.
It's better to cook it too long than not long enough. If you don't cook it long enough, it will melt and you'll have icing everywhere. If you cook it too long it will be a little lumpy but it will still taste great.
This stuff is basically crack.