Heat the oven to 350 degrees. Coat a 13x9-inch (3-quart) baking dish with 1 tablespoon of the butter.
Cook the noodles in salted water as directed on package; drain.
Meanwhile, melt 1 tablespoon of the butter in 10-inch skillet over medium heat. Add the asparagus, bell pepper, and onion. Cook 3 to 4 minutes or until crisp-tender, stirring occasionally. Stir in the thyme, lemon peel, salt, and nutmeg.
In a large bowl, mix the cottage cheese, milk, sour cream, and eggs. Fold in the cooked noodles and vegetables. Spoon the mixture into the baking dish.
Melt the remaining 1 tablespoon of butter and drizzle over the top of the casserole.
Bake for 45 to 55 minutes or until it is set in center and top is golden brown. Let stand for 10 minutes before serving.