Nocino might just be the most delicious booze you've never heard of. Sweet, nutty, woodsy, and surprisingly versatile, this slightly bitter Italian liqueur made from underripe, green walnuts boasts a centuries-long history in its native country. 

Though popular for both medicinal and recreational uses in its homeland, nocino is lesser-known outside of the Italian population. This is a shame, as the unexpected and delicious complexity it adds to drinks is undeniable — and it just might be the exact ingredient you need to take your sour cocktails to the next level.