Making the beurre blanc:
1. In a cold saucepan, combine your finely minced shallots, white wine, and champagne vinegar. Reduce the liquid by half.
2. Monter au beurre: while the liquid is at a rolling boil, add your room temperature butter piece by piece to the saucepan while whisking continuously to create an emulsion.
3. Turn off the heat, and season with salt, white pepper, and lemon juice to taste. Reserve and keep warm.
4. Optional: the shallots may be strained from the sauce.
Steam the fish and green beans:
1. Season the fish on both sides with salt, pepper, and a squeeze of lemon. Cook the fish filet in a steam oven or in a steamer with the blanched green beans for about 5 minutes or until the fish is done.
2. On your plate, spoon the warm beurre blanc with shallots over the fish and green beans