I adore yoghurt (home-made, of course) in every way possible, but for some reason, I'd never tried to make a yoghurt ice-cream. A famous Asian iced yoghurt chain is now strutting its stuff in Kota Kinabalu but their ic-cream is sickly sweet and 1 scoop costs as much as 1 1/2 litres of home-made yoghurt.

When I was in Singapore last week, Julia and I visited the superb Singapore Garden Festival, where we spent 5 hours drooling over orchids, pitcher plants, "fantasty gardens" (plus, I admit, indulging in a bowl of piping hot rice porridge with century egg and chicken to warm us up after 2 hours of freezing temperatures). One of the exhibitors kindly gave me several kaffir limes, those small, bumpy-skinned fruit from the tree whose double leaf has the most heavenly fragrance and is used in Thai and Nonya cuisine. I have a tree in my garden but although the providesmore leaves than I need, it has never flowered and given me fruit.

Anyway, I put the singapore kaffir lime and yoghurt together in the following recipe. By the way, the sickly colour of the lime in the photo is because I'd deep-frozen it. They're lovely bright green for the first hour or so after they defrost (but can be grated while still frozen) but then they take on this awful colour. The yoghurt ice tastes great, sort of herbal or even reminiscent of newly cut grass. You could, of course, substitute lemon rind and lemon juice for the lime. And if you have an ice-cream maker, you don't have to keep processing and re-freezing it as I do.

400 ml plain yoghurt (home-made or the best quality you can find)
grated zest of 1 kaffir lime
60 ml lime juice
130 ml sugar syrup* or a mixture of honey and sugar syrup
a liberal splash of limoncello or light rum

* I make mine with by boiling water with several chunks of Chinese yellow rock sugar, which is a mixture of cane sugar and honey and gives the syrup an unctuous texture and delightful flavour

Whisk all ingredients together in a bowl, then taste and add more syrup if needed; remember, when it's frozen the sweetness is less noticeable. Put in a freezer until it starts setting along the edges; whizz in a blender, return and freeze again. Whizz once more to break up the ice crystals, returning to your freezer container, cover with foil and return to the freezer until about 20 minutes before you need it. Then transfer it to the lower part of the fridge to soften. Serve, preferably with crisp sweet wafers.