Step 1Roast the chiles on a hot griddle or in a hot skillet until fragrant, 30 seconds. Remove them to a bowl of hot water to soak until softened, 15 minutes. Drain.
Step 2Meanwhile place the tomatoes in a large saucepan, cover with water and bring to a boil, cooking until softened, about 5 to 7 minutes. Drain and let cool, then core.
Step 3Place the tomatoes, chiles, onion and garlic in a blender and puree. Strain through a coarse strainer or sieve. Pour into a saucepan and simmer 15 minutes. Set aside.
Step 4In a large skillet, heat the oil to 275 degrees and fry the tortillas until slightly firm, a few seconds each side. Remove to paper towels and drain.
Step 5Drain off the excess oil from the skillet. Add the sauce and the tortillas, stirring to combine, and simmer until the tortilla strips are softened, 5 minutes.
Step 6Serve the chilaquiles on a platter, sprinkled with the queso fresco and decorated with the onion slices and parsley.