Preheat oven to 425 degrees. Line a large baking sheet with foil.
Place the tomatillos, on the prepared baking sheet and roast in the preheated oven for 10-15 minutes until starting to turn golden brown.
Meanwhile, heat the olive oil in a large skillet over medium-high heat. Add in the chopped jalapeno and onion and cook, stirring occasionally for 4-5 minutes until onion is soft.
Add the garlic to the pan and cook stirring constantly for one minute, remove the pan from the heat.
To the bowl of a food processor or high powered blender add in the roasted tomatillos, jalapeno mixture, cilantro, lime juice, salt, and cumin.
Pulse (don't blend) a few times until desired salsa consistency is reached. Taste the salsa and add more salt or cumin if desired.
Pour the salsa into an airtight container and chill in the refrigerator until cooled through. Salsa is good stored in the refrigerator for up to 5 days.