Walnuts can be a problem, because so often they’re either dry or old. French housewives have two tricks for reviving them: They soak them in sugared water or hot milk overnight or gently toast them in a skillet to release their natural oils.
Place the crème fraîche in a funnel lined with a paper coffee filter and let drain until reduced to ¾ cup, about 3 hours. Or boil the heavy cream until reduced to ¾ cup. Refrigerate until ready to use.
Drain the snails and toss with the wine in a small bowl. Cover and refrigerate until ready to cook. Remove from the refrigerate about 30 minutes before you plan to