Sudachi: it's a Japanese small round green citrus fruit, but don't eat it! It is a sour citrus with notes of fresh ginger used as food flavoring in place of vinegar. It has been considered an "indispensable companion" to eating matsutake mushroom. It is also used to garnish soba and udon noodles. It makes a delicious and refreshing ice cream and is a wonderful exotic addition, replacing lemon juice, in sweets such as refrigerator lemon pie or baked lemon bars.