Preheat the oven to 180°C.
Boil the cream in a saucepan for two minutes until slightly thickened.
Whisk in both mustards, horseradish, and lemon juice then season with salt.
Keep the sauce warm without allowing it to boil again.
Debone and cut the salmon into four equal portions.
Season salmon with salt and pepper and dredge lightly in flour.
Mix 2 tablespoons of horseradish with the egg yolk.
Dip the top of each fillet into the egg mixture.
Combine breadcrumbs with parsley and press onto the coated salmon.
Heat oil in a frying pan and sear fillets crust-side down with butter for three minutes.
Turn the salmon over and roast in the oven for five minutes.
Stir chives into the sauce and serve with the salmon fillets.