Without saying “drink me” on the label, the new St.-Germain elderflower liqueur is as compelling as the vial on the table in “Alice in Wonderland.” With its elegant belle époque bottle, its musky-sweet aroma hinting of Meyer lemon and its mouth-filling honeyed pear flavor, it is hard to resist. On its own, this 40-proof liqueur, said to be the first made from fresh elderflowers hand-picked in the Alps and macerated in eau de vie, is pretty intense unless it’s cut with ice and a splash of soda. But it adds a lush fruitiness to a glass of Champagne or white wine. A number of bartenders are using it in cocktails, the most alluring of which is the St.-Germain 75, based on the classic French 75. Adam Landsman, the bar manager at the Modern, combines a shot of gin, a shot of St.-Germain, a little lemon and simple syrup over ice in a tall glass and fills the glass with sparkling wine.