Heat the broiler on your oven and roast the tomatillos in the broiler for about 8 minutes, flip them over and roast 8 more minutes or until the skin is blistered. Allow to cool and the coarsely chop.
In a mixing bowl mash the avocado with a fork and then add the remaining ingredients including the roasted tomatillos. Mix until well combined, add extra salt and pepper to taste.