Using a cheese grater, grate half the white onion and the tomatoes into a medium bowl. Add white vinegar, dried oregano and salt to taste. Set aside.
In a medium skillet, fry chorizo, remaining onion, garlic and half of the serranos until chorizo is fully cooked and vegetables are softened. Remove from pan and set aside.
In the same skillet, scramble the eggs. Remove from pan and set aside. Wipe skillet clean.
Heat the skillet to medium-high. Heat 1 tortilla for 30 seconds on each side, remove and fill with 1 tablespoon chorizo mixture and 1 tablespoon eggs, roll and place in a dish (making sure it doesn’t unroll). Continue until all tortillas are filled.
In a deep-sided skillet, heat one inch of oil to 350 degrees (or until the oil bubbles when a piece of tortilla is lowered in). Fry tortillas in batches of 4 to 5, starting with seam-side down and holding with your tongs for 8 to 10 seconds to ensure it doesn’t unroll in the oil. Cook for 2 minutes on each side until golden brown and crispy.
Serve alongside dipping sauce, and garnish with chopped cilantro, serrano peppers and Cotija cheese.