Tkemali
Georgian sauce made from sour cherry plums with garlic and herbs, fruity, tart and mildly hot.
Tkemali is a Georgian sauce made from cherry plums, which turns out green, yellow or red depending on the variety and ripeness; the fruit is cooked, sieved and seasoned with garlic, coriander, dill, chilli and usually pennyroyal. It tastes distinctly sour, fruity and herbal with little sweetness, and is more pourable than chunky. In Georgia it is eaten with grilled meat, potatoes and beans, but it also serves as a souring ingredient in stews. Bottled versions are sold in Russian and Eastern European grocery shops and online; in summer it can be made at home from cherry plums, which grow wild in many places.
Substitute:
There is no true equivalent; the closest is a homemade purée of unripe, sour plums cooked with garlic, fresh coriander, dill and chilli. Ready-made plum butter or plum jam is too sweet and misses the clean sourness, even sharpened with lemon juice it remains only a distant approximation, and without pennyroyal the characteristic minty, bitter note is lost.