This addictive dish, which is essentially a Mexican version of fondue, is traditionally served as an appetizer. Queso fundido is best eaten straight from the oven when the cheese is still hot and bubbling. Simply scoop the cheese onto tortillas and roll it up like you do when preparing tacos.
Add 1 teaspoon of oil to a medium-sized pan over medium-high heat, add the chorizo and cook until crispy. Transfer the sausage to a small oven-proof dish and drain the excess fat from the pan. Reduce the heat to low and sauté the garlic and pepper with the remaining teaspoon of oil in the same pan, until soft and translucent. Working in increments, slowly add the cheeses, mixing gently to combine fully.
Meanwhile, turn on the broiler and immediately transfer the cheese to the dish with the chorizo, add the cayenne and granulated onion and mix together. Finish the queso fundido under the broiler for 1 minute, or until the cheese bubbles.
Serve immediately with tortillas.