It may seem like a small thing, but one of the happiest consequences of the renewed interest in cocktails and the ingredients that go into them is the resurgence in the vermouth category. Noilly Prat used to make a dry vermouth for the North American market; it recently discontinued that version and began exporting the European formula. And Dolin, one of the best French vermouths, was reintroduced in December 2008. There are several excellent brands of crème de cassis. Most come from Dijon, France.
Place 2 cubes of ice in a highball glass. Over these pour 3 ounces dry French vermouth and 4 dashes crème de cassis. Add a twist of lemon peel and fill the glass with seltzer or vichy.