Roast the peppers. Place the peppers, one or two at a time, directly on top of a high flame on the stove. Use kitchen tongs to turn them as each side chars. When they're evenly charred, remove them from the burners, place them in a large stainless steel bowl and cover it tightly with plastic wrap. Let them steam for 10 minutes. (Alternately, you can put them in a brown bag and fold/roll the top to make it airtight.)
Once they’re cool enough to work with, use your hands to peel off the skin and remove the stems. Use a paring knife (or your hands) to make a slit vertically down each pepper to open it. Remove the seeds and trim away the membranes from the inside. Pat them dry on both sides with paper towels. Then roughly chop them.
Toast the pine nuts. Add the pine nuts to a small sauté pan and place it over medium-low heat. Shaking the pan gently to move them around often, heat until they’re golden, very aromatic and look oily. Set them aside to cool.
Make the pesto. Add the peppers, with the roasted garlic, toasted pine nuts, Parmesan, basil, salt and a few turns of pepper, to the a food processor fitted with the blade attachment. Blend until it’s relatively smooth, add the oil and blend once more. Season to taste with salt and pepper if necessary.
If you want a thicker more spreadable pesto, strain it. Be sure to save the liquid as it’s absolutely delicious on its own and is a sauce in and of itself.