Set a large (10-inch) skillet over medium heat. Lay in the garlic and chiles and roast, turning regularly, until soft and browned in spots, about 10 minutes for the chiles and 15 for the garlic. (If you’re really short on time, you can soften them in a microwave: Cut a slit in each garlic clove and combine with the chiles in a microwavable bowl. Cover with plastic wrap, poke a few holes in the top and microwave on high for 30 seconds.) Cool until handleable, then slip off the garlic’s papery husks. Roughly chop everything (no need to remove the chile seeds).
In a blender or food processor, combine the garlic and chiles with the cilantro, parsley, olive oil and salt. Process, stopping to scrape down the sides if necessary, until nearly smooth (it should look a little like pesto). Transfer to a pint-size jar and store, covered, in the refrigerator, where it will last several months.