This is a less traditional Ranchero Sauce recipe that you can use for huevos rancheros, chile rellenos or omelets. The sauce uses fresh tomatoes, roasted chilaca chiles, onions, Mexican oregano cilantro, and fresh mushrooms. The addition of the mushrooms makes this a nice thick, hearty vegetarian sauce. If you can't find good, flavorful tomatoes then you are better off using a good quality canned plum tomato.
You can find substitutes for chilaca chiles at this link.
In a large skillet, sauté chilies, onion, garlic, mushrooms, and chiles in 1 tablespoon of virgin olive oil, at very low heat until the mushrooms are cooked through.
Add the chopped tomatoes, cilantro and Mexican oregano and simmer for 15 minutes or until the sauce is thickened to your liking.
Taste to check to see if the mixture needs salt. Pass additional fresh chopped cilantro to top the finished dish.
Use this link for help learning how to roast fresh chile peppers.