Spiced Beer Fondue

1 bottle (12 oz) light colored beer, such as ale or lager
2 C shredded Gruyere cheese
1 C shredded Cheddar cheese
2 T flour
1 t coarse grain mustard
Salt and Pepper

Bring beer to a boil in a medium saucepan; simmer over medium heat until it stops foaming, about 5 minutes. Reduce heat to low.

Toss cheeses with flour in medium bowl. Gradually add cheese mixture to beer, stirring constantly. Add mustard, salt and pepper. Cook, stirring constantly, until cheeses are melted. Transfer to fondue pot over low heat.