Preheat oven to BROIL on high and place oven rack in the middle of the oven.
On a large sheet pan, place the tomatillos, jalapeño, shallots, and garlic. Roast for 3 to 5 minutes, until tomatillos and shallots start to blacken. Flip vegetables over and roast for an additional 2 minutes, until all the vegetables have softened and are slightly charred.
Remove pan from oven and allow vegetables to cool down to room temperature for about 15 minutes.
Make salsa verde:
Transfer roasted vegetables and the juices to a food processor or blender. Add the cilantro, lime, and salt. Pulse to combine and blend until salsa verde is smooth.
Store in an airtight jar and refrigerate for up to 1 week.