Preheat the oven to 200°C degrees. Cut the tomatoes in half and put them in baking tray.
Cut the onion into 4 wedges (don’t peel it) and tuck them between the tomatoes together with the chilli and garlic cloves (unpeeled). Scatter the oregano on top, season with salt & pepper, then drizzle with oil. Roast for about 20 minutes or until the veggies have softened.
Take the tin out. Let the veggies cool completely, then remove their skins and put their flesh into a food processor together with the cooking jus. (Remove the chilli seeds, if you don’t want it too spicy!).
Pulse for a few seconds until you get a coarse paste.
Cut the avocados in half, remove their stone and scrape out their flesh into a bowl.
Add half of the avocado flesh, the coriander leaves and the lime juice to the blender. Whizz until you get a textured paste. Add the remaining avocado and whiz for a few seconds until the desired texture is achieved. (Or use a fork to mash it for a more rustic version)
Taste it. Season with salt and pepper and add more lime if needed. If you want it have a real kick, serve it with a few drops of Tabasco, chopped chili pepper, pinch of chili flakes or cayenne.