Place an oven rack on one of the top two shelves (see notes). Cover a baking sheet with aluminum foil. Toss the tomatillos, onion, jalapeño, and garlic with just enough olive oil to generously coat them.
Broil for 10 -15 minutes, shaking the pan or using tongs to flip the veggies once or twice, until vegetables are lightly charred. The more you char the vegetables, the smokier the salsa will taste.
Allow to cool briefly, then place the broiled vegetables in a food processor or blender along with the cilantro, lime juice and salt. Pulse several times to combine (you can create a smooth or chunky salsa here depending on personal preference).
Serve with tortilla chips or alongside your favorite recipes. Refrigerate leftovers for up to 3 days.
For broiling, most recipes recommend using the top oven rack. I personally like to use the second shelf down so I can keep a better eye on things to avoid burning ingredients.You can use more hot peppers to intensify the heat level. Use 1 garlic clove instead of two if you prefer a milder garlic flavor.Yields approximately 1 1/2 cups total.