Prepare and roast or grill the red peppers (skip this step if using jarred peppers)Quarter the peppers and remove the stems, seeds and membranes. If Grilling: Lay the directly on the grill, skin side down. Grill until the skins are blackened and have collapsed, about 10 -15 minutesIf Roasting: Lay the peppers on a foil-lined baking sheet, cut side down and roast for 15-20 minutes or until the skins are very dark and have collapsed.Let the peppers cool until comfortable enough to handle and then peel the skins off and discard them. TIP: place the peppers in a paper bag or a bowl covered in plastic wrap to steam for about 10 minutes helps loosen the skin.
Prepare the tomatoes (skip if using canned tomatoes)Bring a pot of water to boiling. Make an X on the bottom of the tomatoes and place in the boiling water for no more than a minute. Remove from the pot with a slotted spoon and place them into a bowl of cold water to cool them just enough to handle. Drain and then peel the tomatoes over the bowl to catch all the juice using a knife or just your fingers.
Peel and roughly chop the onion and peel and mince the garlic.Heat 2 tablespoons of olive oil in a large stock pot over medium high heat.Saute the onion until soft and translucent, about 1-2 minutes. Add the garlic and cook for another minute.Add the cayenne, pepper flakes or paprika, if using, and stir through.
Roughly chop the tomatoes and roasted peppers and add to the stock pot along with the juice from the tomatoes and the salt and pepper..Add 2 cups of water to the pot.Allow the mixture to come to a low boil and let simmer for 15 minutes.
Taste for seasoning. Add balsamic vinegar and salt and pepper if needed.The balsamic vinegar will add a touch of acidity and brightness, but may not be needed if the tomatoes are particularly acidic.
Roughly purée the soup, adding more water if it's too thick. I like the soup to be a little rustic, with some texture instead of a completely smooth purée.Stir in the chopped fresh herbs ( the more the better!), reserving some for garnish
Serve with a little olive oil drizzled on top and some fresh herbs for garnish
Notes
If using fresh peppers and tomatoes they can be prepared ahead of time.The finished soup will keep in the refrigerator for 4-5 days, or 2-3 months in the freezer.