Preheat the oven to 190°C.
Cut the onion and beets into 4 wedges each. Cut the peppers in half, remove the seeds and stems, then cut the flesh again in half.
Put the onion, beetroot and pepper in a large baking dish.
Mix the oil with the oregano, cumin and garlic, then brush the veggies with this, using a silicon brush.
Cover the dish with foil and bake in the oven for 25-30 minutes or until the veggies are tender.
Remove the dish from the oven, then transfer the veggies and jus to a saucepan.
Add the stock pot, chipotle paste and the water, then bring to a boil. Cook for 5 minutes, then purée it with a stick blender until you get a thick, silky soup.
Add the drained beans and bring back to the boil.
Turn off the heat and stir in the chopped coriander leaves and lime juice.