Place onion, garlic, and tomatillo in a small pot with enough water to cover the vegetables. If using a serrano pepper and beef bullion, add it on this step.
While the tomatillos cook, sauté the guajillo chiles on 1/2 tablespoon of vegetable oil for about 45 seconds on each side.
Repeat this process for the Chiles de Arbol. Remove from skillet and add to the pot with the tomatillos.
Cook the tomatillos until they start to turn yellow and before they crack. Cooking them too long they will become bitter and too tangy.
Once the tomatillos have cooled off, add all ingredients to a food processor or blender and mix well. Season with salt & pepper if needed.
Try this salsa at your next party! It goes perfect with chips & guacamole on the side. I always keep some in my refrigerator to eat with eggs, quesadillas!