Preheat the oven to 190°C. Heat the oil and butter in a pan and fry the mushrooms for 2-3 minutes.
Add the spring onions and red pepper and cook for 3-4 minutes. Remove from the heat and add the bacon, potatoes and cheese. Gently combine.
Transfer the mixture to a well-greased tin or ovenproof round casserole. Whisk the eggs together and season well with salt and pepper.
Pour the egg mixture over the mushroom mixture and bake in the oven for 25 – 30 minutes, or until the centre is just cooked. Allow to stand for 5 minutes, before unmoulding or slicing from the tin.
Serve warm or at room temperature, topped with extra crispy bacon, fried mushrooms and a rocket salad.