WHOLE-EGG LEMON BUTTERCREAM

Steps:

• Bring 1 cup water to just below a simmer in a medium saucepan over medium-low heat. Using a handheld whisk, combine eggs, sugar, and salt in the bowl of a stand mixer. Place bowl on top of saucepan (it should not touch water) and cook egg mixture, whisking constantly, until lightened in color, thickened slightly, and an instant-read thermometer registers 160°F. Remove from heat and beat with stand mixer fitted with the whisk attachment on medium speed until completely cooled and tripled in volume, about 10 minutes. Add butter, 1-2 Tbsp. at a time, beating well after each addition until fully incorporated. Add vanilla and lemon curd and beat on medium-low speed until just combined.
• Do Ahead
• Buttercream can be made and refrigerated up to 5 days in advance or frozen up to 1 month. To use refrigerated buttercream, let sit at room temperature until soft, at least 2 hours. Beat with stand mixer fitted with the paddle attachment on medium speed until smooth. If texture is not smooth, beat in a little water, 1 tsp. at a time. To defrost, transfer buttercream from freezer to refrigerator to thaw overnight. Then follow the instructions for using refrigerated buttercream.