If you are continuing from the bifteck saute beurre bercy simply start this sauce in the pan you just removed your steak from.
Otherwise you might want to get a saucepan out or you’re not getting very far here ;-P
What you need:
(…. a saucepan)
¼ cup dry white wine or vermouth
1 tbsp minced shallots
(same suggestion as before with the almost puree)
1 tbsp meat glaze or ½ cup brown stock/ beef bullion
big pinch of pepper
½ cup of butter
1 to 2 tbsp minced parsley
Boil the wine with that shallots (or onions), meat flavoring/stock and pepper until the liquid has reduced to about 1½ tbsp. Let it cool.
Cream the butter well (mix it up to a light cream) then a tablespoon at a time beat the butter into the wine flavoring. Beat in the parsley and season to taste.
(For bifteck saute beurre bercy, now simply pour your beurre bercy over your steak and serve.)