French Buttercream

Combine 340g sugar and 43g corn syrup in a heavy saucepan; heat to 120°C (soft-ball stage).

Whisk 1 whole large egg and 5 large egg yolks in a heatproof bowl until pale and foamy.

Slowly drizzle the hot syrup into the whisked eggs while beating continuously until thick and cool, about 10 minutes.