Remove the stems and seeds from the guajillo and ancho peppers and add to a medium saucepan. Destem the jalapeno and serrano peppers and add to the pan. If you would like a more mild flavor, remove the seeds also.

Add the onion and garlic cloves to the pan and add enough water to cover the ingredients. Bring to a boil over for about 15 minutes or until all the ingredients are tender, about 15 minutes. Let cool to room temperature.

Strain and add the contents to a blender. Blend until smooth. Strain the sauce to make sure it is smooth.