Cook the pasta in salted water following pack instructions. Melt the butter in a large frying pan over a medium heat. Once foaming, stir in the shallot with a pinch of salt and a few twists of black pepper. Cook for 5-6 mins until softened and lightly golden, then turn the heat to low.

Move the pasta straight from the water into the frying pan, then stir in the crab, a ladleful of pasta water and the parmesan. Mix very thoroughly, tossing well and adding more pasta water if needed, until glossy.

Serve with more parmesan and a sprinkling of black pepper and chives, if you like.