Directions

Toast the chiles in a hot pan until fragrant. (about 10 to 15 seconds per side)
Allow chiles to cool and then remove stems, seeds and veins.
Char the onion, tomatoes and garlic in a hot pan.
Place the chiles, onion, tomatoes, garlic oregano and marjoram in a pot with just enough water until the ingredients are almost covered.
Bring to a boil and then reduce the heat to low.
Simmer for 15 minutes to reconstitute the chiles and soften the veggies.
Blend the chiles, onion, tomatoes, garlic, oregano marjoram and the soaking water until smooth. It usually takes about a minute.
Add water little by little if necessary to blend. You may have to blend in two batches
Strain the mixture.
Add two tablespoons of cooking oil to a hot pan add the strained sauce to fry it.
Reduce the heat and simmer for 30 minutes until the sauce has thickened.
Add salt to taste.
Allow the sauce to sit for at least 2 hours so that the flavours meld.
Warm the sauce before serving.