Time 1h25m Yield 24 Number Of Ingredients 6 Steps:
Beat egg with a fork in a small, heavy saucepan. Mix in sugar and milk. Heat on medium-low heat, whisking constantly, until it just starts to boil. Continue beating rapidly until mixture thickens to a thin custard consistency. Remove from heat and cool completely, about 1 hour. Beat butter in a bowl with an electric mixer until light and creamy, about 5 minutes. Add cooled custard, 1 to 2 tablespoons at a time, beating well after each addition. Beat in rum and vanilla extract. Keep beating until buttercream is very light and fluffy.
Time 40m Yield 4 cups. Number Of Ingredients 5 Steps:
In a small heavy saucepan, combine sugar and water. Bring to a boil; cook over medium-high heat until a thermometer reads 240° (soft-ball stage), 3 to 4 minutes. Meanwhile, using a stand mixer, beat egg yolks in a large bowl on high speed until thick and foamy, 8-10 minutes. , Slowly pour hot sugar syrup over egg yolks while beating continuously. Continue beating on high until mixture cools to room temperature, 15 to 20 minutes. , Gradually add butter, a few tablespoons at a time, beating on medium after each addition until smooth. Beat in vanilla. Use immediately.
