Boil potatoes until tender. Drain and mash, then set aside.
Meanwhile, cut fish fillets into bite-size chunks (or to suit). Spray a large baking or casserole dish with cooking oil spray. Arrange fish over the base of dish and set aside.
Heat oil in a large frying pan over medium heat and cook onion for a few minutes, until beginning to soften. Add remaining vegetables and cook for 5 - 7 minutes, until softening.
Remove from heat and add cream and chilli flakes, stir. At this point you can also add salt and pepper, to taste, if desired.
Pour creamy vegetables on top of fish in the prepared dish. Spoon over mashed potato and smooth over the top evenly to cover vegetables competely. Sprinkle over the grated cheese.
Place into preheated oven, cook for a good 60 minutes. Leave to sit for 5 minutes after removing from oven as it will be piping hot! Serve with crusty bread, or even some steamed brocolli & cauliflower with cheese sauce, yum!
Microwave in a small amount of water the pumpkin, carrot, capsicum, spinach and peas for 10 minutes, to save time. Then drain and add to frying pan with onion. Cream & chilli can now be added at this point.
Use any vegetable you like in this dish, it's very versatile! I have used sweet corn kernels, asian gai larn, sweet potato (kumara), leek, or a packet of frozen mixed vegetables. As long as the vegetables are diced small, you can mix and match to suit your family's tastes. Also, adding some flaky pastry on top of the mashed potato is another great variation I have used before. You can leave as it is or sprinkle with cheese. It makes for a deliciously crispy topping! You may have to use fan-bake for the last 20 minutes if you add pastry.