Yield: about 2 cups
1 tbsp. canola or vegetable oil
¼ cup onion, finely chopped
1 jalapeño pepper, seeded and finely chopped
12 oz. white American cheese, shredded* *White American cheese can be found at the deli counter in most grocery stores.
4 oz. Monterey jack cheese, shredded
¼-2/3 cup milk
1 tomato, seeded and finely diced
2 tbsp. cilantro, minced
Heat the oil in a medium saucepan over medium-high heat. Add the onion and jalapeño to the pan and cook, stirring occasionally, until tender, about 5 minutes. Reduce the heat to medium-low. Add both of the shredded cheeses and ¼ cup of the milk. Whisk or stir until completely melted. Mix in the tomato and cilantro, and add additional milk gradually as necessary to achieve desired consistency. Transfer to a warmed serving bowl and serve immediately.
http://www.annies-eats.com/2011/01/17/queso-blanco-dip/