Separate the cauliflower into florets and steam/ boil/ microwave until soft. Follow the tips in my keto mashed cauliflower recipe.
Add the butter, soured cream, cheddar, chives, nutmeg and salt. Blend in a food processor or with an immersion blender until smooth.
Preheat oven to 200 Celsius/400 Fahrenheit (electric) or 180C / 360 F fan.
Fish filling
Fry the onions and garlic in olive oil over a low / medium until soft and translucent, around 3 minutes. Do not burn.
Add the white wine. Turn up the heat to high and reduce by half.
Add the grated courgettes, cream, lemon zest and herbs and simmer for 5 minutes. Season with salt and pepper.
Assembly
Put the fish fillets in a casserole dish and pour over the sauce.
Spread the cauliflower mash on top and run a fork over the top to make lines.
Bake in the oven for 40 minutes or until the top is browned.
Sprinkle with some fresh parsley and serve.
Notes
8.1g net carbs per serve. Makes 6 servings. Option to layer 2 sliced hard boiled eggs over the fish filling. You can use a mix of white fish or even salmon and add prawns. All work well. Adding celery and fennel to the sauce taste good, too.Don't miss out on the lemon zest. It really makes the recipe!!If you do not want to use wine, substitute with a good quality fish stock or even chicken broth.