Cook the pasta following pack instructions. Once it’s cooked, drain, reserving some of the water, and tip it back into the pan. Add the soft cheese, lemon juice and gravadlax or smoked salmon with some pepper and mix well. Add a little of the pasta water to help form a creamy sauce, and heat through.
Add most of the chives, stir, and divide the pasta mixture between bowls. Serve with the remaining chives scattered on top.