Heat the oil in a large saucepan over a medium heat, add the onions, carrots and celery, and fry for 8 mins until softened, stirring occasionally. Stir in the stock and chipotle, bring to the boil, and simmer for 10 mins.

Ladle half of the soup into a blender and blitz. Pour the blitzed soup back into the pan, then add the chicken, peas, lemon juice and some seasoning (use smoked salt, if you have it). Simmer for 5 mins to warm through.

Stir the lemon zest into the crème fraîche along with the garlic and 2 tbsp water to loosen.

Divide the soup between bowls, swirl in the crème fraïche and top with the chilli flakes, if using.