Just happened to stumble onto this site. I see there are others out there who know that the chili con queso at the restaurant formerly known as Tippy's Taco House in Laurel, MD (now Toucan Taco House) is the best there is. I recently obtained the following recipe from someone who also loves Tippy's queso. He was a total stranger I just happened to meet at a soccer party - the father of one of the team's players. Somehow the conversation turned to mexican food and when we discovered our common love of this queso, he offered to e-mail me the recipe. I have not yet tried to make this queso. Please post after you try it and let us know how it came out. Thanks.

Tippy’s Chili con Queso:

Spice Mix:

1 tsp. salt
1 tsp. Red Pepper
1 tsp. Cumin
1/2 tsp. Black Pepper
1/2 tsp. Garlic Powder

Cheese Mix:

1 lb. American Cheese (personally we recommend “Land o’ Lakes”)
1/2 to 1 cups Water

Vegetable Mix:

2 TBSP. Chopped Onion
1 Small can Green Chilies
2-3 TBSP. stained chopped Tomatoes

Instructions:

Add cheese, water and vegetable mix. Heat in a double boiler or microwave carefully. Once the cheese is melted, add about 1 TBS spice mix to taste.

Notes:

We usually use Pace Salsa instead of chopping onions, tomatoes and green chilies. We usually add more than the recommended amount of Vegetable Mix.