2 c. water
1 1/4 c. dry pinto beans
1 medium onion, chopped (about 1/2 c.)
1/4 c. butter
3/4 tsp. salt
1/2 c. shredded cheese

Mix water, beans, and onion in 2 quart saucepan. Cover and heat to boiling; boil 2 minutes. Remove from heat. Let stand 1 hour. Add just enough water to cover beans. Heat to boiling; reduce heat. Cover and boil gently, stirring occasionally, until beans are tender, about 1 1/2 hours (add water during cooking if necessary). Mash beans. Stir in butter and salt until butter is completely absorbed. Add cheese (optional).