Place a cast iron pan over a medium heat, add a knob of butter and once its foaming add the flour, stirring to combine. Once the flour smells beautifully caramel-like begin to whisk in the milk, adding a little at a time.
To the sauce add the bay leaves, crème fraiche and cheese, and continue stirring until the sauce has thickened and the cheese has melted.
Tip in the left over veg, turkey, pigs in blankets and stir until all the ingredients are generously covered in the creamy sauce. Check the seasoning and add a pinch of salt if needed. Turn the heat right down low and let the pan gently blip away.
Put a pan of water to boil. Add a big pinch of sea salt to the pot and tip in the pasta. Cook until al dente and then tip away the water, reserving one small mug of starchy pasta water.
Pour the pasta into the sauce along with a little of the starchy water. Stir to combine the creamy sauce. Finish with a good pinch of black pepper and an extra grating of cheddar.