In a large bowl toss tomatillos, serrano peppers, & onion in avocado oil.
Preheat Bull Grill to medium heat and grill tomatillos, peppers, and onion for about 4 minutes on each side or until grill marks begin to form.
Remove tomatillos, peppers, and onion from grill and place in pot. Fill pot with water until tomatillos, peppers, and onions are barely covered with water. Bring to a boil on your Bull Side Burner and reduce to a simmer for 10 minutes.
Remove from heat and let cool. Blend until your desired consistency with salt, lime juice, and garlic. Add in peppers one at a time until you’ve reached your desired heat preference.
Garnish with green onions and cilantro. Serve chilled or hot.