2 packages (10 ounces each) frozen French-style green beans
1/2 cup chopped onion
1 tablespoon minced fresh parsley
2 tablespoons butter
1 cup sour cream
1 teaspoon grated lemon zest
1 teaspoon salt
1/4 teaspoon pepper
1/2 cup shredded cheddar cheese
Cook green beans according to package directions. Meanwhile, in a saucepan, saute onion and parsley in butter until tender. Stir in the sour cream, lemon peel, salt and pepper. Drain beans; add sauce and gently stir until coated.
Transfer to a greased 1-qt. baking dish. Sprinkle with cheese. Broil 6 in. from the heat until cheese is bubbly, about 5 minutes.