Preheat the oven to 220°C/200°C fan/gas 7. Line a baking tray with baking paper. Brush the cobs with 1 tbsp oil. Sprinkle with the paprika; roast for 25 mins and cool.
Meanwhile, for the temper, heat 2 tbsp oil in a pan over high heat, add the raisins, cumin, cloves, peppercorns and cinnamon; cook for 5 mins, swirling the pan; allow to cool. Blitz in a high-speed blender with 2 tbsp water to a paste. Set aside 1 tbsp for the cashews (if making).
Heat 2 tbsp oil in a pan over medium heat. Add the onion and cook for 5-10 mins. Add the garlic for 2 mins. Stir in the spice paste, cocoa powder and thyme; cook for 1 min. Add the tomato purée and stock; stir. Simmer for 15 mins.
Shave the kernels off the corn with a knife; add to the soup with the black beans. Cook for 5 mins, add the cabbage; cook for 5 mins more.
For the cashews (if making), heat 50ml oil in a frying pan; stir in the reserved 1 tbsp spice paste. Add the cashews and fry for 3-4 mins; cool.
Squeeze in the lime juice; divide between bowls. Top with coriander, and jalapeño and cashews, if liked.
