1. Preheat the oven to 200°C/400°F/Gas 6 and prepare the ingredients: peel and roughly chop the onions, peel and cut the butternut squash into bite-sized chunks, trim and roughly chop the courgette and deseed and roughly chop the pepper.
2. Spray a pan with Fry Light and fry the sausages for 3-4 minutes until lightly browned. Remove from the pan and place in a casserole dish with the onions, butternut squash, courgette and red pepper.
3. Meanwhile, mix together the chilli flakes, garlic salt, oregano, sweetener, tomatoes and Bovril and pour into the casserole dish. Season well and cook in the oven for 25-30 minutes. Remove from the oven and serve immediately.