Smashed Potato-Broccoli Casserole

1 lb potatoes
1 cup chopped broccoli
1/4 cup diced onion
1/4 cup cottage cheese
1/4 tsp dill weed
1/4 tsp salt
1/8 tsp pepper
1/2 cup sour cream
1 1/2 oz shredded cheddar cheese

Quarter potatoes, cover with water and bring to a boil. Reduce heat; simmer 20 minutes or until tender. Drain potatoes, reserving 3/4 cup of cooking liquid. Return potatoes and reserved liquid to pan; mash with a potato masher until slightly chunky. Add broccoli, onion, cottage cheese, dill weed, salt, pepper and sour cream. Spoon mixture into sprayed casserole dish. Bake at 375 for 35 minutes. Sprinkle with cheese and bake 5 minutes longer.