Unless you have quick cooking pasta, set your pasta to cook while you make the sauce. Once it has cooked, drain but reserve the pasta water and cover the pasta to keep warm.
Soak the sundried tomatoes in boiling water while you cook everything else (unless they are in oil in which case skip this step and just slice).
Cut the bacon in relatively thin slices. Warm a large skillet/frying pan or saute pan over a medium-heat and add the bacon, stirring now and then to avoid it sticking too much and so it cooks on both sides.
While it's cooking, dice the onion and garlic relatively finely. Slice the sundried tomatoes and roughly chop the spinach.
Add the onion and garlic to the bacon once it is starting to brown, around 5 mins.
Once the onion has softened, another 5 min or so, add the cream, the little bit of pasta water, sliced tomatoes and spinach.
Cook for another 2-3 minutes until the spinach wilts down then add the pasta and stir through well so the pasta is well covered with the sauce. Add a little more pasta water if needed.
Serve, topped with some freshly grated parmesan.