There’s two ways with these chestnuts. The original recipe says to shell and blanch the chestnuts. But I love the roasted flavour and couldn’t bear to simply blanch them. Plus they’re easier to shell when they’re roasted.Start by taking a small sharp knife and cutting a X into the bottom of each chestnut. Turn on the oven to 200oC and let heat up. Place them on a baking tray or a wire backing rack with small holes so it doesn’t fall through. Let them roast in the oven until they’ve clearly split open. Let cool before, shelling (this includes taking off the middle ‘lining’ not just the outer shell).Place them in a medium to large pot with 4 cups boiling water.Add in the chopped onion, celery, bay leaf parsley and paprika.Cover and boil for 30 minutes.Press through a strainer or cheesecloth, stir in 2 cups milk, and return to the stove.Rub together the butter and flour before adding to the soup. Remember to actually rub it together and not just add it separately, otherwise it clumps.Let heat up for one minute, sprinkle with some salt, and press it through a metal strainer with the back of a spoon or use a purée sieve if you happen to have one. Or purée in a blender, always easier, even if not correct.Serve hot.