Toast the guajillos: Heat a dry skillet over medium heat. Toast each guajillo for 10–20 seconds per side until aromatic but not blackened. Remove and set aside.

Roast the vegetables: In the same skillet, lay Roma tomatoes cut-side down and cook until blistered and soft, about 5–8 minutes. Add the 1/4 onion and garlic cloves to the skillet and roast until softened and slightly charred in spots.

Simmer the sauce base: Put toasted chiles, roasted tomatoes, onion, and garlic into a pot. Add just enough water to cover the ingredients and stir in the chicken (or vegetable) bouillon. Bring to a gentle simmer and cook for 8–10 minutes so flavors meld.

Blend and strain: Transfer the mixture to a blender and purée until smooth. Push the sauce through a fine-mesh sieve into a bowl to remove skins and chile bits for a velvety texture.

Crisp the tortillas: Preheat oven to 400°F (200°C) if baking. Arrange tortilla triangles on baking sheets, spray lightly with oil, and bake for 10–15 minutes until crisp and lightly golden. Alternatively, shallow-fry in 1–2 cups neutral oil in batches until golden, then drain on paper towels and salt lightly.

Warm and season the sauce: Return the strained sauce to the pot and simmer gently for 3–5 minutes. Taste and adjust salt (or more bouillon) as needed. If the sauce is too thick, add a splash of water to loosen.

Toss chips with sauce: In a wide skillet, add a single layer of chips and spoon warm sauce over them—toss gently so chips are coated but still retain some crunch. Work in batches if serving multiple plates.

Fry the eggs: In a nonstick pan, fry eggs sunny-side up or to your preferred doneness. Season with salt.

Plate and garnish: Place sauced chips on each plate. Top with a fried egg, sprinkle with crumbled Cotija or feta, scatter chopped white onion and cilantro, and serve hot.