lemon balm
A fresh herb of the mint family with soft, toothed leaves and a gentle lemon scent.
Fresh lemon balm is not stocked in every supermarket; look for it as a potted plant at garden centres and farmers' markets, or in Turkish and Eastern European shops, and it grows easily in a garden or window box. The dried leaves sold for tea have lost much of their fragrance and add little to cooking.
Substitute:
Fresh mint with a little grated lemon zest comes close to the scent, but it tastes cooler and stronger, so use less.