This is my favorite frosting because it is so versatile and not too sweet. Though intimidating to make initially, it is a skill quickly mastered!
This recipe is based on Rose Beranbaum’s Mousseline frosting in The Cake Bible. It is a large batch Italian Meringue. I love to make this frosting because it freezes well, and has a delicious creamy flavor. My variation on her original came about when I was trying to develop a recipe that would taste good served cold. My plan was to use butter and shortening, hoping that it would stay softer when chilled. I added 2 cups of butter (of the 2 1/2 called for in the recipe) and went to get the half cup of shortening. While I was fetching the shortening, I left the frosting mixing. When I came back it was a beautiful consistency ready to use for frosting. I took a quick taste and liked the lighter texture and feel better than with the extra half cup of butter. The rest of my modifications from the original are in the method. I also leave out the alcohol she suggests. They’re small shortcuts that add up to a great time (and stress) savings. I’ve even used frozen butter for the first two sticks to speed the cooling time. Use the recipe and follow the detailed steps below.
Start with room temperature egg whites and butter, and have your sugar, cream of tartar and water ready. You’ll need a glass measuring cup, a heavy pot, stand mixer and good candy thermometer.
- Have everything you need ready; egg whites measured and all other ingredients out. Make sure things are at the right temperature.
- After you put your egg whites in the mixing bowl, make sure to rinse out the measuring cup and grease it with Pam.
- Start heating your sugar syrup over high heat. Place your candy thermometer and stir constantly until sugar has dissolved. Once dissolved you may stop stirring.
- Beat your egg whites at high speed until foamy, then add the cream of tartar.
- When they reach soft peaks, add your sugar and beat until stiff peaks form.
- Prepare your butter by cutting it into tablespoon sized pieces. Have it ready to use for step 8.
- When the sugar syrup reaches 248, pour it into the measuring cup. Stop the mixer and immediately pour a small amount into the prepared egg whites. Mix and add the rest of the syrup while the beaters are spinning. Beat until cool (about 1/2 hour).
- Add the butter to the egg white mixture one at a time until they are incorporated. You will need to lower the mixer speed from time to time so that nothing splashes out. It will look thinner and curdled before it mixes up to a beautiful mousse like consistency.
- Keep beating until it reaches that beautiful consistency. Add vanilla (about 1-2 Tablespoons). Use immediately or refrigerate for up to a week. This freezes up to 6 months.