This is a French buttercream, with syrup beaten into egg yolks to form a smooth, light cream with a luxurious taste. A hint of mocha contrasts perfectly with a dark chocolate cake.
The original recipe called for sugar, which is 50 percent glucose and 50 percent fructose, but I substituted dextrose (a powdered form of glucose) because a growing body of research indicates that eating fructose causes major health issues. If you’re a fructose malabsorber like me, fructose can cause other problems as well. So I have two reasons for not adding fructose to anything I eat. By the way, the fructose in fruits and vegetables is an issue only if you are a fructose malabsorber, so don’t let the bad press about fructose stop you from eating them.
While this recipe is definitely an indulgence, it uses a lot less sweetener than many buttercream recipes. A number of recipes I looked at used up to 4 cups of powdered sugar. Corn syrup, which is glucose, is what makes this recipe succeed, so don’t substitute something else for it. Read the labels carefully to make sure you’re buying pure corn syrup and not a brand mixed with high fructose corn syrup. Manufacturers sometimes mix the two products.
Feel free to substitute any liqueur for the Kahlua. While Kahlua does have some sugar in it, I only used two tablespoons, so the amount of fructose in it is minimal. If you prefer a chocolate frosting, see the variation at the end of the recipe. I use large organic eggs, which tend to have smaller yolks than regular large eggs, so I weigh the yolks to make sure that I use the correct amount. I highly recommend that you weigh things- it’s the most accurate way to measure ingredients and there are fewer dishes to wash.
Don’t worry about the butter if you’re lactose intolerant, as butter is low-lactose according to “Food Intolerance Management Plan”, by Sue Shepherd. Most people with lactose intolerance can handle about 4 grams of lactose per serving of food without experiencing problems (page 29). As always, only eat what your body can tolerate, and only you know what that is.
Kahlua Buttercream Frosting, adapted from The Cake Bible
Enough frosting for two 8 inch cake layers and 12 cupcakes, two 9 x 1 1/2 inch cake layers, or three 9 x 1 inch cake layers
112 grams egg yolks, room temperature (6 to 7 large egg yolks)
150 grams dextrose (1 cup + 2 tablespoons)
164 grams corn syrup (1/2 cup)
454 grams unsalted butter, room temperature (1 pound), 1 tablespoon reserved
2 tablespoons Kahlua
Coat a small heat-proof bowl with the reserved tablespoon of butter. Place the bowl next to the stove. Use either a stand mixer or a large mixing bowl and a hand-held mixer. Put the egg yolks into the bowl and beat them until frothy. Combine the dextrose and corn syrup in a small pan and heat on medium-high. The mixture will be stiff at first, so stir constantly, until the dextrose dissolves and the mixture comes to a full, roiling boil. The finished buttercream will be thin if the syrup doesn’t come to a full boil. Pour the syrup into the buttered bowl to stop the cooking.
Pour a tiny bit of the syrup into the yolks and beat for 5 seconds. Turn off the mixer and add a little bit more syrup, then beat on high for another 5 seconds. Repeat this process until all of the syrup is mixed into the yolks; continue mixing until the yolk mixture is cooled. It will be a pale yellow. Use a rubber spatula to scrape the sides of the bowl that held the syrup to make sure all the syrup and butter is mixed into the yolks.
With the mixer running, add small chunks of butter to the yolks one at a time. Wait for each chunk to be incorporated before adding the next one. When all of the butter is mixed in, add the Kahlua and mix thoroughly. The buttercream will last for 6 hours at room temperature. If you are not frosting your cake immediately, transfer the buttercream to a bowl, cover it tightly, and store it in the refrigerator for up to a week. The buttercream can be frozen for up to 8 months. Bring it to room temperature before using. If needed, use a mixer to beat it again to restore the texture. Don’t beat cold buttercream or it will curdle.
30 grams (1/3 cup) cocoa powder
70 grams (1/2 cup) dextrose
56 grams (1/4 cup) coconut oil or non-hydrogenated organic shortening
2 tablespoons Kahlua, optional
Melt the oil or shortening in a bowl and mix in the cocoa and dextrose until blended. Set aside to cool. Add the chocolate mixture to the buttercream and mix until thoroughly combined. Taste and add the extra Kahlua if you want. There will be the faintest hint of coconut if you use coconut oil, but it adds a subtle touch to the taste.