First make the sauce. Over a medium heat, melt the butter in a large, heavy-based saucepan. Add in the flour and whisk together thoroughly.
Gradually add in the milk, whisking well between each addition so as to thoroughly add dried parsley along with garlic granules,nutmeg and pepper mix it in.

Add in the fish stock pot/cube and whisk it thoroughly in until dissolved into the sauce. Add in the cream and whisk in.
Simmer for 1–2 minutes, whisking as you do so.

Add the cod fillets to the hot sauce, shaking the pan to coat them in the sauce. Poaching the cod in the sauce means that the flavour from the fish infuses the sauce.

Simmer for 4–5 minutes until the fish is opaque, carefully turning over the fillets halfway through cooking so that they cook evenly.

Once the fish is cooked, Garnish with parsley and serve at once. I like serving this with fresh garden peas and mashed potato.

#Note:
I used cod fish in this recipe you can use haddock, sea bass or salmon as well.

I used dried parsley you can used add fresh parsley if you wish.