Buttercream, with its rich and creamy taste yet light and velvety smooth texture, is the king of cake frosting. Buttercream may be used for filling, frosting, and decorating cakes and pastries. Buttercream, whether made in a Swiss, French, or Italian style, has a basic ingredient: high quality, unsalted sweet butter.
Swiss Buttercream: Swiss has a creamy buttery taste that is absolutely delectable, easy to make, silky smooth, and not too sweet. This Buttercream is made with egg whites and sugar that are first heated together to about 130 degrees and then beaten into a fluffy meringue and cooled, and finally softened butter is beaten into the mixture.
French Buttercream: is made by whipping whole eggs and egg yolks to a thick foam and then adding hot sugar syrup, and then whipping in softened butter. The egg yolks used in this Buttercream results in a lovely butter yellow color.
Italian Buttercream: is made in the same way as French Buttercream but using egg whites instead of egg yolks. Start with a basic Italian Meringue just like that used for Lemon Meringue Pie, then whip in softened butter to make a Buttercream.
See Buttercream Recipes:
Buttercream Tips
Buttercream is an emulsion that will break down and separate if the ingredients are not at the right temperature.
Swiss Buttercream:
When making Swiss Buttercream, the egg whites and sugar are first heated over a pan of hot or simmering water to about 130 degrees before whipping into meringue. At this temperature all the sugar granules should be dissolved and the mixture should feel completely smooth when rubbed between your fingertips. Test the temperature using an instant read thermometer, and if the heat is correct and sugar granules dissolved remove from the heat. As the meringue is whipped it cools down to room temperature. The meringue must be cooled before the butter is added otherwise the butter would simply melt when added. To test the temperature of the meringue the outside of the bowl should feel cool to the touch, or just barely warm.
Butter: Butter used is all Buttercream should be softened to room temperature, normally 68 to 70 degrees. Remove the butter for your recipe from the refrigerator and let it sit on your counter. Generally 20 to 30 minutes before using is sufficient time to achieve the correct softness; however the time may vary depending on the warmth in your kitchen. Cutting the butter into one inch pieces will speed up the softening time. To most accurately determine the temperature of the butter, use an instant thermometer. Alternatively, test for room temperature butter by gently pressing the top of the stick of butter with your finger. If an indentation remains but the stick of butter still holds its shape then it should be perfectly softened. If your finger sinks down into the butter it is too soft and should be placed back into the refrigerator for a short time to firm back up. It is best not to soften butter in the microwave as it can start melting quickly and become too soft, or soften unevenly.
French Buttercream:
To prevent the syrup from going over 238 degrees F, remove the syrup from the heat just before it reaches 238 degrees. Have a glass measuring cup near the stove and immediately pour the hot syrup into the glass cup to stop the temperature from rising.
Ribbon Test: When making French Buttercream, the whole eggs and egg yolks are beaten until the mixture drops in ribbons. To test for ribbons, lift the beater 2 or 3 inches out of the beaten egg yolks. The yolks should be light in color and fall to the surface in thick “ribbons.” You normally want a three second ribbon which means from the moment the ribbon hits the surface until it disappears from sight and sinks back into the body of the foam; you have been able to count one one-thousand, two one-thousand, and three one-thousand.
Super-Fast Thermapen Thermometer:
TheBakingPan Recommends: This is the BEST instant read thermometer I’ve used for making sugar syrups and meringues for Buttercreams; the ThermoWorks Splash-Proof Super-Fast Thermapen Thermometer is incredibly fast, accurate, and well worth the investment. 
Originally designed for professional users, the Super-Fast Thermapen Thermometer is used by celebrity chefs, cooking magazines, foodies, bloggers, and competition BBQ teams, and has become the top cooking thermometer for home use.
Gone are the various instant read, candy, and meat thermometers I’ve previously used; instead, I use my Thermapen Thermometer for checking room temperature baking ingredients, sugar syrups, melting and tempering chocolate, baking bread, making pastry creams, caramel, and candy, along with cooking and barbequing meats and fish, and checking oil temperatures for deep frying. Thermapen Thermometer available here.
Basic Buttercream Tips:
Adding Sugar Syrup to Eggs: After cooking the syrup, immediately start pouring it into the eggs. Stop the mixer as you do this because you don’t want to get any sugar syrup on the beater. Otherwise, when mixing, the beaters will spin the syrup around the sides of the pan, making a sugar mess along with not getting all the syrup into the eggs.
Eggs and Sugar Syrup Too Warm: If the egg and sugar syrup mixture is still warm when you add the butter, the butter will melt and the Buttercream will become a mess. If this happens the mixture needs to be cooled. Place the bowl over a bowl of ice water and beat with a wire whisk until the mixture cools enough allow the ingredients to emulsify and become creamy.
Butter Too Cold: If the butter is too cold when added to the egg and sugar syrup mixture the mixture will not blend and the texture will look like curds of cottage cheese. If this happens the mixture needs to be warmed. Place the bowl over simmering water for about 5 seconds while stirring with a rubber spatula or wooden spoon, be careful not to overheat. Return the bowl to the mixer and beat on medium speed until the mixture comes together and is creamy.
Separating: Don’t worry if the mixture appears to separate or curdle after you’ve added the butter, just continue to beat with the mixer and the mixture will become smooth. If the completed Buttercream has been sitting for quite awhile before using and appears to be separating or liquid at the bottom of the bowl it just needs to be rewhipped. Use a wire whisk or beat with the mixer until it comes together.
Too Soft: If the Buttercream seems too soft for spreading or piping, chill the Buttercream in the refrigerator for 10 to 15 minutes before using.
Storing: Buttercream can be refrigerated up to 5 days or frozen up to 6 months in an airtight container. If frozen, thaw in the refrigerator overnight or for several hours at room temperature. Before using, bring to room temperature and beat with the paddle attachment on low to medium speed until smooth, about 5 minutes.