2 lbs. Brussels sprouts
2 Tbsp. butter
1 onion, chopped
1/4 tsp. dried thyme
1/4 cup flour
2 cups milk
1 1/2 cups shredded Gruyere cheese
3/4 tsp. salt
1/4 tsp. pepper
Topping:
1 1/2 cups fresh bread crumbs
1/2 cups shredded Gruyere, Cheddar or Gouda cheese
2 Tbsp. butter
Trim Brussels sprouts; cut an X in base of each. In saucepan of boiling salted water, cook Brussels sprouts for 7 to 9 minutes, or until tender-crisp. Drain and chill under cold running water; press out excess water with towel. Cut in half if large; place in shallow greased 8 cup casserole dish.
In saucepan, melt butter over medium heat; cook onion and thyme, stirring occasionally for 5 minutes or until softened. Sprinkle with flour; cook, stirring, for 1 minute. Add milk;
cook, stirring, for 6 to 8 minutes or until thickened. Remove from heat and stir in cheese, salt and pepper; pour over Brussels sprouts.
Topping:
In bowl, stir together bread crumbs, cheese and butter. (Make ahead: Cover Brussels sprouts and topping separately, refrigerate for up to 1 day.)
Cover and bake Brussels sprouts in 375�F oven for 30 minutes. Uncover and sprinkle with topping; bake for about 20 minutes or until golden and bubbly.