Turn on the broiler. Place all the tomatillos, poblano, onion, and garlic on a lined baking sheet. Spray with oil and then sprinkle the cumin and coriander on the veggies.
Place the sheet in the broiler and broil (about 6 inches from the fire) for about 4 to 5 minutes, or until it starts bubbling.
Take the sheet out of the oven, flip all of the ingredients, and broil for another 4 minutes or until the ingredients look nicely charred.
Combine all the broiled ingredients into a food processor or blender with the cilantro and avocado and blend until smooth.
Video
Notes
Want some spice, add one or two jalapenos or serranos when you broil and blend your vegetables.
If you don't have vegetable oil spray, you can simply lightly oil the ingredients.