Preheat a grill pan.
In a bowl, toss the tomatillos, jalapeños, onion and garlic with 2 tablespoons of the oil.
Grill over high heat, turning occasionally, until the vegetables are slightly softened and charred in spots, 5 minutes.
Let cool slightly, then transfer to a food processor.
Pulse until coarsely chopped.
Add the cilantro, lime juice and the remaining 2 tablespoons of oil and pulse until chunky.
Season with salt and pepper and serve warm or at room temperature.
