I'm giving directions for using 1/2 each of the cheeses using the large boxes of the cheeses. But you can make a large batch if you have a large double boiler.
1/2 of a large box of Kraft american cheese
1 large onion sliced into long strips
1 and 1/2 large bell peppers seeded and ribs removed and cut into thin strips.
1 fresh jalapeño seeded and ribs removed and cut into thin strips.
3 table spoons of a picante sauce.. this was not part of the recipe but I found it makes is delicious.
Purchase equal amounts of Velveeta cheese and Kraft american cheese... don't spare expense here buy these cheese the plain sort. Kraft american is in a blue box. it doesn't matter how much you use as long as it is equal amounts and if fits in the double boiler with enough room to add the veggies and whole milk.
I purchase the large ones and cut each in half for making the queso two times.
Prepare a double boiler by placing enough water in the bottom but not to touch the bottom of the pan make sure the pan is large enough for the amount of queso your making.
Cut both cheeses into 1 inch cubes and place into the double boiler, add the onions and the jalapeño and Bell pepper and SIMMER ON LOW for several hours until onions and bell pepper are very soft and making sure to stir often and add milk as necessary. NEVER let it boil or it will be grainy.
Once the peppers and onion are soft add the picante at this time. Do not let cook much longer after the picante addition as it will curdle the sauce if not careful.
If your sauce is starting to curdle add more milk to the cheese and water to the double boiler pan and turn down the heat.