On a sheet pan, add the tomatillos, onions, jalapeños, and garlic.
Drizzle with olive oil.
Mix to coat well.
Place under a broiler on HIGH for 4-5 minutes.
Remove the onion and garlic.
Check the tomatillos.
If they are not fully charred, place them back under the broiler for 2-3 more minutes.
Once they are done, remove and let cool slightly.
To a molcajete, add salt and garlic.
Grind up the garlic with the salt.
Add the jalapeños.
Grind up the jalapeños as best as you can.
Add whole tomatillos one at a time.
Gently press down at first, or the tomatillo will squirt out all its juices.
Then continue mashing.
Do this for all the tomatillos until there are none left.
Add the diced onions and chopped cilantro.
With the pestle, mix to combine.
Taste for salt.
Serve with chips or as a topping for your Mexican favorite dishes.