1 tablespoon olive or vegetable oil
1/4 cup white onion, diced
1 large jalapeno or serrano, seeds and stem removed; diced
16 ounces white American cheese, shredded or cubed
4 ounces Monterrey Jack cheese, shredded
3/4 cup cream or half-and-half
1 (10 oz.) can diced tomatoes and green chilies
1-2 roma tomatos, seeds removed and diced
1 small bunch cilantro, roughly chopped

Heat the oil in a saute pan. Cook the onion and pepper until softened and reduce heat to medium-low. Add the cheeses and 1/2 cup of the cream. Stir until mostly melted. Add the can of diced tomatoes and green chilies, the diced tomatoes, cilantro, and additional cream a little at a time until you reach desired consistency. Serve with chips or fresh tortillas.