Preheat the oven to 200°C (390°F)
Start with the cauliflowe topping. Cut into small chunks and steam for 10 minutes. Remove from the steam and let the water evaporate off the cauliflower for a couple of minutes before placing into a food processor. Add 50g of butter and a pinch of salt and blend until smooth. Set aside and keep warm.
Begin the sauce in a medium heat pan whilst the cauliflower is steaming. Add the butter, chopped onion and bay leaves. Fry for 5 minutes until the onion is translucent but not browned.
Add the cream, milk and cloves and bring to a simmer. Add the fish and poach in the pan on a low heat for 10 minutes, stirring regularly.
Remove the fish from the pan using a slotted spoon and put into the baking dish you're going to bake the pie in. Continue to simmer the sauce, raising to a medium heat.
Remove the clove and bay leaves from the sauce and add in 1 1/2 cups of cheddar, dijon mustard and the pinch of nutmeg
Once the cheese has melted into the sauce add the spinach, peas and parsley to the sauce and bring back to a simmer for 5 minutes, stirring regularly
Now prepare the pie. Pour the sauce over the fish and mix to combine. Top with the cauliflower mash, then drag the prongs of a fork over the mash to rough up the surface. Sprinkle the top with the remaining cheddar cheese and bake for 25-30 minutes until the cheese is golden brown and bubbling on top.
Allow the pie to cool for 10-15 minutes, then serve with a garnish of fresh parsley. Serve immediately or let cool and store for up to 4 days in the fridge