Chop the huitlacoche, onion, tomatoes, and garlic.
In a small saucepan, saute the huitlacoche in 1 tbl oil over medium heat for about 10 minutes. Transfer to a bowl.
Add 1 tbl oil to pan and saute the onion, tomatoes and garlic, stirring frequently, until the onion is translucent, about 5 minutes. Add to huitlacoche and stir until well mixed.
Heat a skillet over medium heat. Place corn tortilla in pan and sprinkle half with cheese. Spoon huitlacoche mixture onto cheese, then sprinkle with more cheese, keeping it all on only half the tortilla. Using a spatula, fold tortilla over.
When the bottom is turning golden and the cheese has melted, flip and cook on the other side. Remove from heat and repeat with remaining tortillas.
Serve with your favorite salsa.
Notes
The filling can also be used as a salsa for tacos.