1/2 glass would be just about 1/4 to 1/3 of a cup of wine, dry white wine is the correct kind tho.

Not OP but beurre blanc really is a classic easy sauce. 1 shallot, half a glass of wine, the juice of half a lemon, 40 grams butter and 10cl sour cream.

Finely mince the shallot, put it to simmer with the lemon juice and wine until reduced by about half.

Now it the only « choice », you can strain, keep or blend the shallot from the liquid. Then right before serving melt the butter in your mix, then add cream. Voila.

Then you just have to sear scallops and that should be it.