Charred Tomatillo Guacamole

This guacamole is the best home made guacamole I have ever had. It is a perfect blend of spices and avocados and veggies.  I used 1 Hawaiian pepper instead of Serrano peppers and it was still good.  You could probably use jalapeno peppers as a substitute too.  Thanks to my friend Cherish Stout for sharing the recipe with me.  It's actually from her father-in-law, Bill Stout.  I hear he's a pretty good cook.  I could have probably eaten most the bowl, but I had to step away:)

Ingredients:
6 oz tomatillos (6 or 7), husked and rinsed.
1/2 small red onion, finely chopped
3-4 fresh serrano chiles, seeded (optional) and finely chopped
1/2 cup finely chopped fresh cilantro
1 tsp salt
1/2 tsp black pepper
2 large avocados (1 lb total)
1/2 tsp chili powder
1/4 tsp cumin
3/4 cup sour cream (may use low fat or fat free)
1 small garlic clove, chopped

Directions:
Preheat broiler.  Broil tomatillos in a flameproof shallow baking pan about 4 inches from heat until tops are charred, 7 to 10 minutes.  Turn tomatillos over with tongs and broil until charred, about 5 minutes more.  Combine onion, chiles, cilantro, salt, and pepper in a large bowl.  Add tomatillos 2 at a time, mashing with a fork or pestle to form a coarse paste.  Pit and peel avocados.  Add avocados to mixture and continue mashing until incorporated but still chunky.  Note: you can seed about half of chiles for moderately spicy guacamole, all of them for mild.  Guacamole may be made 8 hours ahead of time and chilled.  Bring to room temperature before serving.