Homemade Refried Beans --Delicious

1 1/2 c dry pinto beans
4 cups water.
Bring to boil in a saucepan, then let it sit for 1 hour off of heat. Add 1 chopped onion and water to cover. Cook at a slow
boil for 1 1/2 hours or until beans are tender. Stir once in a while and maybe add a little water. Blend, don't drain unless
you have a lot of water, in a blender and stir in 2 tsp butter. Salt to taste and have a 1/2 c cheddar cheese, or other cheese.
Serve warm with salsa and Mexican food.