Preheat the oven to gas 7, 220°C, fan 200°C. Toss the butternut squash in 2 tablespoons of oil, put in a deep-sided baking tray or roasting tin and bake for 10 minutes. Add the bacon, cut into 2·5cm (1in) pieces, and bake for a further 10 minutes.
Meanwhile, in a blender, whizz the flour, egg, milk and a pinch of salt into a double cream-like batter. Stir in the thyme. When the bacon’s ready, pour the batter evenly over the bacon and squash. Bake for 30-40 minutes, until golden and puffed.
Heat the remaining oil in a frying pan. Add the onions and gently cook until soft (about 15-20 minutes). Add the sugar and cook until dissolved. Stir in 1 tablespoon of flour. Pour over the stock, bring to the boil, simmer for 5 minutes until thickened. Cut into wedges; serve with the gravy.
For top tips on protecting you and your family when preparing raw meat and poultry, visit Food Safety in the Home and view the full Food safety at home video.