1. Drain the pilchards well and set the sauce aside for another day.
2. Cut bacon into little pieces and fry in a frying pan until crispy.
3. In the end; add the spinach until just starting to wilt then remove it from the heat.
4. For the sauce, melt the butter in a saucepan. Stir in the flour and cook for 1-2 minutes. Take the pan off the heat and gradually stir/whisk in the milk to get a smooth sauce. Return to the heat while constantly stirring and bring to a boil.
5. Add grated cheese to the sauce and allow to melt on low heat.
6. Cook pasta according to the instructions on the packet.
7. Drain the pasta and mix in the cheese sauce.
8. Add the bacon, spinach and pilchard and check the seasoning for salt and pepper. Serve hot.