2 lb brussels sprouts
2T butter
1 onion, chopped
1/4 t. dried thyme
1/4 c. flour
2 c. milk
1 1/2 cups shredded Gruyere cheese
3/4 t. salt
1/4 t. pepper
TOPPING:
1 1/2 cups fresh bread crumbs
1/2 c. shredded Gruyere, Cheddar or Gouda cheese
2T butter
Trim brussels sprouts; cut X in base of each. In saucepan of boiling salted water, cook brussels sprouts for 7 to 9 mins, 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 min or until softened. Sprinkle with flour; cook, stirring, for 1 min. Add milk; cook, stirring, for 6 to 8 mins 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, refrigerate for up to 1 day.)
Cover and bake brussels sprouts in 375°F oven for 30 mins. Uncover and sprinkle with topping; bake for about 20 minutes or until golden and bubbly.