Cook the pasta according to the packet instructions and get on with the rest while it's cooking.
Preheat oven to180c/160cfan/350f/gas4.
Heat the oil in a medium saucepan and cook the bacon until starting to crisp - about 3 minutes.
Add the leeks, and cook until beginning to soften - about 2 minutes.
Stir in the garlic and sun dried tomatoes, then the crème fraîche and the multi grain mustard. Heat gently.
Add a ladleful of water from the pasta pot and stir to loosen the sauce. It may seem to runny at this stage, but it's going in the oven so will thicken up and reduce.
Remove from heat and stir in the grated cheddar and spinach.
Drain the pasta and add to the sauce, mixing it in gently.
Pour the whole lot into your baking dish, scatter with remaining cheddar and cook in the oven for 10 minutes, or until the cheese and gold and bubbling on top.
Serve immediately with mozzarella and basil foccaccia.