1. Preheat the oven to 200˚C, gas mark 6. Roast the swede with ½ tbsp oil for 25-30 minutes, until tender. Meanwhile, fry the onion in the remaining ½ tbsp oil for 10 minutes, until soft. Add the garlic and spices for 2 minutes.
2. Mix the swede and onion; purée ½ in a food processor, then mix it all back together. Season and stir in most of the coriander. Divide into 8 cakes, each 1cm thick. Coat each in the egg, then the breadcrumbs.
3. Fry the cakes in about 100ml oil over a medium heat for 2 minutes each side, until golden and piping hot. Drain on kitchen paper; serve with the reserved coriander, plus yogurt and lemon wedges, if liked.