4egg whites120grams, if they weigh more it is fine, I often have egg whites that are larger and 4 will weigh 130grams, it is fine to use them.
3- to 4sticks(1stick 113grams) of room temperature unsalted butteryou can experiment by adding less, some people like it with less butter, it is up to you.
pinchof salt or 1/2tsp cream of tartar
1tblvanilla extract
Instructions
Combine egg whites, sugar and salt in a mixer bowl, set it over a pot of simmering water and whisk until sugar is dissolved and candy thermometer reaches 160F, continue whisking at this temperature for 5 minutes.
Then set the mixer on your stand mixer base and beat on high until stiff peaks are formed, once the outside of the bowl is lukewarm, to the touch you can start adding soften butter small piece at a time. Beat well. Keep adding all of the butter. Mixture may curdle, this is normal just keep beating using a wire attachment. Add vanilla and other flavorings as desired. For this recipe I used vanilla extract and also oil based maple flavoring.
Notes
If using in the heat of the summer, you can substitute 1stick of butter for shortening that can hold up to hotter temperatures, I personally try to avoid using traditional shortening, you can try using other better for your shortenings that are available. In the hot months I also like to add about 2tbl meringue powder per batch.
To color buttercream I use gel food colorings. I take a small portion of uncolored buttercream (3 tbl to 1/4 cup), I place it into a small microwave safe bowl. I add coloring into the small bowl and stir well, then I microwave it on high for about 5 seconds. Heat activates the color pigments, buttercream will liquifies, this is normal, immediately pour microwaved portion it uncolored buttercream and stir well, if darker colors are desired, repeat the process. If buttercream is too soft for you to pipe you can refrigerate buttercream for 10 minutes until it firms up a little or have a batch with chilled water on hand to cool your hands in between to prevent buttercream softening while you are piping. You freeze buttercream or store in the fridge for up to 2 weeks.