Heat the oil in a saucepan and cook the onion over a medium heat until soft and golden. Add the pepper and butternut squash and cook on a medium-low heat for about 10 minutes, until just softening.
Add the chilli, garlic, cumin and oregano and cook for a further minute.
Stir in the flour and cook for about 30 seconds, then add the tinned tomatoes, stock or water, tomato purée and sugar. Season.
Bring to the boil, then turn the heat down and cook, covered, over a low heat for about 20 minutes. The pumpkin should be tender.
Stir in the drained, rinsed beans. The mixture should be thick but not dry – you may have to add a little more water or stock. Season well.
Bring to a boil again, then turn down the heat and cook, covered, over a low heat for about 10 minutes. The beans shouldn't fall apart during this time – they just need to soak up the flavours around them - so check to see that they’re okay.
Stir in the chopped coriander and check the seasoning.
Serve with boiled rice – brown or white – or warm tortillas, with avocado, chopped spring onions and wedges of lime. Sour cream and or grated Wensleydale or Lancashire cheese or crumbled feta also work well.
This recipe does leave you with half a tin of tomatoes but that’s roughly what I use for a tomato sauce for two anyway. Or you can just double the recipe and put a batch in the freezer – it freezes well.
See our collection of Mexican recipes for more kitchen inspiration.