Amaretto

An Italian liqueur flavored with almonds or apricot kernels — both give that marzipan character. It's sweet, nutty and typically 21–28% ABV, well below standard spirits.

Usually yes, since it's built on almonds or apricot kernels and sugar rather than grain. Check the label if you're highly sensitive, as base spirits vary by brand.

The amaretto sour is the classic — amaretto, lemon and a touch of egg white. It also makes a Godfather with Scotch, and a splash in coffee is a dessert on its own.

Its sugar makes it very stable. Unopened it lasts for years, and an opened bottle stays good for a long time in a cool, dark cupboard — though the almond aroma slowly fades.