Thinly slice the onion and roughly chop the garlic. Peel and dice the squash. Dice the carrot.
Heat a little oil in a large, heavy-based pan then add the mince. Season with salt, stir for a couple of minutes. When the mince has changed colour transfer to a plate.
Add more oil to the pan and gently cook the onion and garlic until soft.
Add the chopped vegetable, put a lid on and gently sauté for 8 minutes, until tender.
Add the spices, stir for a minute, then add the tomato purée and chipotle paste. Stir to coat well. Pour in the tomatoes and the stock. Bring to the boil , put the lid on and turn down the heat. Simmer for about 20 minutes until the sauce is nice and thick.
Drain the beans. Add the beans to the stew and cook for 5 minutes or so, until warmed through. Stir through the coriander.
Serve with a dollop of sour cream or a lime wedge.