Ingredients

• 1  cup sugar
• 1/4  cup water
• 6  egg yolks, slightly beaten
• 2  tablespoons hazelnut liqueur
• 1-1/2  teaspoons vanilla
• 1-1/2  cups unsalted butter, softened

Directions

1. In a heavy medium saucepan combine sugar and water; bring to boiling. Remove from heat. Gradually stir about half of the sugar mixture into egg yolks in a medium bowl. Return all of the egg yolk mixture to the saucepan. Bring to a gentle boil; reduce heat. Cook and stir for 2 minutes. Remove from heat. Stir in hazelnut liqueur and vanilla. Cool to room temperature.

2. In a large mixing bowl beat butter with an electric mixer on high speed until fluffy. Add cooled sugar mixture, beating until combined. If necessary, chill until spreading consistency. Makes 3 cups.