Yield: ~ 10 cups of buttercream
Ingredients
10 large, fresh egg whites (300 g)
2-1/2 cups (500 g) sugar
3 cups (680 g) unsalted butter, cut into cubes and cool, but not cold
1 tablespoon + 1 teaspoon (20 ml) pure vanilla extract
pinch of salt
Instructions
Wipe the bowl of an electric mixer with paper towel and lemon juice, to remove any trace of grease. Add egg whites and sugar, and simmer over a pot of water (not boiling), whisking constantly but gently, until temperature reaches 140°F, or if you don't have a candy thermometer, until the sugar has completely dissolved and the egg whites are hot.
With whisk attachment of mixer, begin to whip until the meringue is thick, glossy, and the bottom of the bowl feels neutral to the touch (this can take up to 10 minutes or so). *Don't begin adding butter until the bottom of the bowl feels neutral, and not warm.
Switch over to paddle attachment and, with mixer on low speed, add butter cubes, one at a time, until incorporated, and mix until it has reached a silky smooth texture (if curdles, keep mixing and it will come back to smooth). *If mixture is too runny, refrigerate for about 15 minutes and continue mixing with paddle attachment until it comes together. Add vanilla and salt, continuing to beat on low speed until well combined.
Add additional flavours, purees, as desired.
Notes
*Keep in airtight container in refrigerator for up to one week, leaving out at room temperature when needed, rewhipping in mixer for 5 minutes.
**Can freeze for up to 6-8 weeks. To thaw, place on counter overnight, and rewhip for 5 minutes with paddle attachment in an electric mixer.
***If buttercream still doesn't have its satiny finish after rewhipping, microwave 1/3 of the buttercream for approximately 10 seconds and add to remaining buttercream in mixer bowl, beating for a few moments to incorporate.
