Sauté the onion and garlic in a saucepan without oil. Stir constantly so they don't burn; cook until they change color.

Once the onion and garlic have changed color, add the mushrooms (cleaned and chopped or sliced as you prefer). Lower the heat and add the epazote, stirring gently. You can add a splash of water, but just a little, since the mushrooms will release their own juices.

Add salt to taste, cover the saucepan, and cook for 10 minutes. You'll notice the mixture becomes juicy—this means the mushrooms have released enough water and are ready!