Add wine, water, garlic, onion, tarragon, parsley, lemon juice to a pan bring to boil. Turn down the heat add cod fillets and simmer until tender about 7-10 Min's.
Remove cod from pan, put in bowl and set aside. Strain liquid into saucepan and return to heat. Add both stocks and sherry stir, in a glass combine cornflour with a little water, add to pan and stir until mixture thickens. Add both the creams, tarragon and parsley stir to mix. Then add the Parmesan cheese and stir until melted, add Gruyere half a cup at a time and stir after each addition until cheese melts, add pepper to taste, remove from heat.
In a large bowl put cod, peas and shrimp pour sauce over and stir gently to combine as you don't want the cod flaking into to small chunks. Place mixture either into individual serving dishes or large oven proof casserole dish. Top with buttered breadcrumbs and sprinkle remaining Parmesan cheese on top. Bake oven for 20-25 Min's or until golden brown at 180c-190c.
Serve by itself or with salad.
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