Cook the pasta until it is al dente. Drain, reserving some of the water to moisten the pasta later, if needed.
While the pasta is cooking, heat half the oil and fry the bacon until just crisp. Remove from the pan and set aside. Add the onions to the pan and cook until golden brown. Add the spinach and stir until wilted.

Add the bacon and spinach mixture to the pasta, followed by the remaining oil, the sweet chilli sauce and half the feta. Serve with the remaining feta crumbled on top.