Roast the peppers - you can either use jarred roasted bell peppers, or make your own from scratch.  Place bell peppers on the top rack of your oven, and broil them under the low broiler setting until flesh is charred.  Remove from oven, allow peppers to cool, and remove charred flesh.

Add Ingredients - to a food processor, add the bell peppers, basil, garlic, walnuts, chili flakes, and white vinegar. Secure the lid, and begin processing over low speed. Open the top of the food processor and stream in the olive oil until the pesto becomes a thick paste.

Taste, and adjust seasoning as needed. Serve with bread, as a dip, or over pasta or pizza, and mangia!