This sauce was made famous by the nineteenth-century Parisian Restaurant Marguery. It’s basically a hollandaise made with the braising liquid from the fillets you cooked with. It would probably be more authentic if you used fish stock instead of wine (or a combination), however I had just cracked a bottle of white and used that instead out of laziness. Also, the original recipe uses shallots, and I used a handful of mushrooms.
1. Preheat an oven to 375 degrees. Season fish with salt and pepper. In a small pan that just suits the size of the fillets (I had two), sprinkle chopped mushrooms and place the fillets on top. Pour over 1/2 cup of white wine (I used a bottle of Viognier white from the Languedoc-Roussillon region. Great value at $13 at the LCBO).
2. Bake until fish is firm, maybe 5 minutes but as much as 10 minutes. Transfer the fish to a plate.
3. Transfer the pan to the stove top and whisk in a few egg yolks over medium heat until the mixture stiffens. Remove from the heat and add about 4ish tablespoons of clarified butter (Ghee works, if you don’t have this stocked in your cupboard go and buy some immediately). Season with salt and pour over the fish. Serve.
I got a version of this recipe from the Sauces book by James Peterson, and then made some modifications to suit my level of motivation and what was in my fridge.
If anyone complains that this sauce will stop your heart, just tell them that you only live once. And please pass me the wine.