Preheat the broiler on your oven and line a baking sheet with aluminum foil.
Place the tomatillos on the baking sheet, cut side down. Add the poblano pepper, jalapeño pepper, onion, and garlic (still in the skin) on the same baking sheet.
Broil until the tomatillos are softened and starting to char and the poblano pepper skin chars, about 8-10 minutes, turning everything halfway.
Remove the poblano peppers from the sheet pan and place in a paper bag or cover with a clean kitchen towel. Allow everything time to cool.
Once the poblano peppers are cool enough to handle, remove the skin and the stem then cut them in half lengthwise. Remove the seeds and cut into 1-inch pieces.
Cut the stem off of the jalapeño pepper and chop into 2-3 pieces. If you want a mild sauce, cut the jalapeño in half lengthwise and remove the seeds and membrane.
Remove the skin from the garlic.
Add the tomatillos, poblano pepper, jalapeño pepper, onion, garlic, cilantro and lime to a blender or food processor. Process until smooth. The sauce will still have a fine texture to it.
Add additional lime juice and salt to taste.