1 cup butter, softened
6 ounces pinto beans, rinsed and drained
4 onions, chopped
1 (10 ounce) can whole peeled tomatoes with juice
1 cup water
3 cups milk
3 cups mashed green sweet potatoes
Preheat oven to 350 degrees F (175 degrees C).
Melt butter in pan (butterfly or outline) of small skillet or saucepan. Melt olive oil with pan or saute pan on medium heat for 5 minutes.
In a large bowl, saute pinto beans, onions, tomatoes and water in olive oil with egg until transparent. Stir in milk and mix with that by hand. Cut in tomatoes and continue mixing with milk until well blended. Add the cheese and bring to a boil.
Place pinto beans, onion mixture and tomatoes in a 9x13 inch baking dish. Pour with boiling milk mixture and top with cheese.
Bake at 350 degrees F (175 degrees C) for 20 to 30 minutes, or until center of the casserole is golden brown and bubbly. Cool in pan for 10 minutes, then flip to the refrigerator. Cool completely.