If using tofu: Preheat oven to 205°C/400°F. Drain and pat tofu dry, hand tear into bite-sized chunks onto a baking tray/sheet. Toss tofu with onion/garlic oil, turmeric, salt and pepper, and bake until golden, ~20 mins.
Finely dice the sweet potato, carrot, red pepper and leeks (if using) into small (1 cm or ~½ inch) cubes.
Heat coconut oil in a large pan on medium heat, add sweet potato, carrots and spices, and cook for 5 minutes.
Add red pepper and leeks (if using) to the pan. Reduce heat to medium-low to prevent burning and cook for a further ~10-13 mins stirring frequently until potato and carrots are tender.
Remove stems from kale and roughly chop. Add kale and onion oil to the pan for the final 5 minutes of cooking. Season to taste with salt, pepper, and chili flakes.
If using eggs: Heat oil or butter in a separate frying pan on medium-low heat. Once hot (water drops should fizzle) crack in eggs, top with salt and pepper and cover with lid. Cook until whites are just set and the yolk is still soft.
If using kale flowers (if you can find them), lightly saute with some garlic oil and a pinch of salt.
Split hash into four and top each portion with a quarter of the tofu or an egg. Add any additional toppings and serve with a slice of low FODMAP bread. The hash will keep well for a couple of days in the fridge, the eggs (if using) are best cooked fresh.