Saw points Sawtooth herb is the perfect name for the long, slender herb with jagged edges that resemble the teeth on a two-edged handsaw. It's also known as culantro and Vietnamese or Mexican coriander - and indeed, its flavour is reminiscent of fresh coriander. Sawtooth herb, though, is much sturdier than delicate coriander leaves, so works better in cooked preparations, although you can eat it raw (it has a stronger flavour than fresh coriander). Sawtooth herb is fairly easy to grow in a sunny spot on a balcony or a windowsill. As with other herbs, trim it back regularly so the flower stalk doesn't have the chance to grow. The herb is used in many countries in Latin America and Southeast Asia, and in parts of the Caribbean. In Vietnam, you'll often find sawtooth herb in the fresh-herb assortment served with fried spring rolls, banh xeo (rice flour, coconut milk and turmeric crepes stuffed with stir-fried vegetables, pork and shrimp) and bowls of noodles, and which diners use to personalise the dishes to their tastes. Sawtooth herb is delicious in duck larb. Mince some duck breast then stir-fry it with garlic, fish sauce, chilli flakes and a little toasted rice powder. Remove the ingredients from the wok and mix in chopped sawtooth herb, minced spring onion, whole fresh mint leaves and some fried shallots. Add fresh lime juice then taste the seasonings and adjust as needed.