Peel rutabagas and cut into small pieces. Place in a large saucepan of boiling water and cook until tender.

Peel, core and chop apples. Add to boiling water about 5 minutes before done. Remove from heat and drain.

Put in food processor and mash. Add butter, salt and pepper.

Spoon into casserole dish. Bake, uncovered, at 325 degrees F. for 20 to 25 minutes.