1. Preheat oven to 190°C/375°F/Gas 5. Lightly grease a deep oven proof casserole dish. 2. Heat the oil in a pan and fry the onions with the sugar until soft. This takes about 5 minutes stirring occasionally. 3. Meanwhile, put the butter, milk and flour into a saucepan and bring to the boil, whisking all the time, until you have a smooth sauce. Season with salt, pepper and nutmeg. Stir in cheese. 4. Next, add the onions and meat to the sauce. Bring to the boil then simmer for 5 minutes, stirring occasionally. 5. Meanwhile, make the crumble by mixing the dry ingredients together. Add the butter/margarine and rub through until a crumble is formed. 6. Spread spinach on base of prepared casserole dish. 7. Pour sauce over spinach and sprinkle the crumble on top. Bake for about 15 minutes until crumble is nicely browned. 8. Serve with salad.