Heat the oil in a large saucepan and add the onion. Cook for 2-3 minutes until beginning to soften, then add the peppers. Cook for another 3-4 minutes until the peppers are just tender.
Add the chilli powder, cumin and paprika to the pan and stir through, cooking for 1 minute. Put the mince in the pan and move around, breaking up with a wooden spoon. Cook for 3-4 minutes until brown all over. Pour in the passata and stock. Bring to a gentle simmer and cook for 30 minutes.
Roughly chop the chocolate and add to the chilli, along with the beans. Stir to combine and melt the chocolate, then simmer for another 15 minutes until the mixture has thickened slightly.
Meanwhile, prepare the rice according to the instructions on the packet. Serve with the chilli and a dollop of crème fraîche on the top.