Serve this quick sauce with purchased rotisserie chicken, or use it as a wrap or sandwich spread. It would also taste great with ham or smoked turkey.
In a small saucepan over medium-low heat, cook onion in hot butter for 6 to 8 minutes or until lightly browned.
Add beer; continue to cook, stirring occasionally, until mixture is reduced to 1/2 cup.
Stir in honey mustard and green onion tops. Heat through.