Ingredients:

1 large red or white onion
4 large ripe tomatoes
1-4 garlic cloves, chrshed
2 fresh serrano peppers
1 Tblsp olive oil
1/4 tsp oregano
small handful fresh cilantro

Wash the cilantro and remove the coarser stems and roots. Chop the onion and tomatoes finely, and the garlic, chilies and cilantro very finely. Put all the chopped ingredients, oil and oregano in a large bowl. Mix thoroughly by hand to blend the the flavors. Place in a non-reactive container and store until needed.