preheat your oven to 200C (gas mark 6) and place an oven tray in to warm
half and de-seed the red peppers. Place on the warmed baking tray and drizzle with the olive oil. Roast in the top half of the oven for 30-40 minutes, until the skins are slightly charred
meanwhile, melt the butter over a medium heat in a large, heavy-bottomed saucepan
add the celery, onion, chilli and garlic to the pan. and gently sweat until the onion is softening and turning translucent
add the chicken (or veg) stock and the chopped tomatoes to the saucepan
when the peppers are roasted, remove the from the oven and transfer them into a plastic freezer or food bag, seal and set aside for 10 minutes. This makes the peppers sweat and makes them easier to peel
peel the peppers, discarding the skins, then chop them and add them to the saucepan. Simmer the contents for 10 minutes
add the handful of basil, roughly chopped or torn, then, using a hand-blender, blitz the soup until it smooth
serve with fresh bread or homemade croutons, garnished with fresh basil and a drizzle of chilli oil