Roast sweet potato & tomato soup

Preheat the oven to 200ºC, gas mark 6. Cut the sweet potatoes into 4cm-thick discs (leaving the skin on). Spread in 1 layer on a baking tray, dotting the onion wedges, garlic and thyme in the gaps. Sprinkle over the sugar and drizzle with 3 tbsp oil. Turn the vegetables to ensure they’re all coated, then roast for 35-40 minutes until the sweet potatoes are soft and slightly caramelised.

Transfer the roast vegetables to a large pan, discarding the papery bits of garlic and any woody pieces of thyme. Add the cherry tomatoes, stock and 500ml water. Bring to the boil, then simmer for 5 minutes. Use a stick blender or upright blender to whizz to a silky soup (take care as it will be hot); season with the salt. Heat the remaining 1 tbsp oil in a small pan over a medium heat, then fry the sage leaves until golden (2-3 minutes); transfer to a plate lined with kitchen paper. Lower the heat slightly, then toast the seeds in the same pan for a few minutes; transfer to the plate. Divide the soup among 6 bowls and top with the sage and seeds.