A nice white wine sauce we have in Spain is:
3 shallots, 2 Cl. white wine, 10 Cl. cream, 250 gr. butter, salt, pepper, juice 1 lemon, little vinegar
Chop shallots very fine. Pour in vinegar and wine and put om high heat till boiling till there's little liquid left (2 or 3 Cl).
Remove from heat and put mixture through a sieve to get rid of the shallots. Add the cream and butter a little at a time beating well all the time. Add salt and pepper to your taste and, lastly, the lemon juice.
Great with steamed fish. You can also add a little chopped parsley just before serving.
Enjoy your meal!