Stewing over a recipe? Baffled by an ingredient? Hilary Biller answers your food questions. Send your queries to food@sundaytimes.co.za or post them to PO Box 1742, Saxonwold, 2132

Q I have been given some lemon grass plants that are doing very well, and I was wondering if there was a way of preserving some of the stem. Can one keep it in brine perhaps? - Gael Constable

A Lemon grass is a blade-like plant used to flavour dishes, particularly curries and soups. Common in Thai and other Asian cooking, lemon grass grows really well in South Africa. It requires a hot, sunny spot and plenty of water. The woody white stalk is used as a flavourant, while the green leaves are stripped off the stalk and discarded. Lemon grass is fibrous and tough and best to add the whole stalk, bruised, to a dish (remove before serving) or chop it very finely and add to the dish.

Once the lemon grass plant is established, it will grow prolifically. It can be preserved in a number of ways. It can be frozen successfully - simply place the stalks, stripped of the greenery, in a plastic bag in the freezer and use from frozen.

Or, chop finely and pack in plastic bags and use to add to soups and stews.

Lemon grass can also be dried. Place on a baking tray in a preheated oven of 100°C for 2-3 hours, leaving the oven door slightly ajar to allow the moisture to escape. Turn a couple of times during the drying. Cool completely and store in plastic bags.

You can use it dried or re-hydrate by soaking in water before using.

I know you can buy bottled lemon grass in brine.

To make your own, remove all the greenery from the lemon grass, place in a pot and cover with water. Bring to the boil and let cook till just tender, then remove and pack into a sterilised glass jar. Make up a brine by combining 2 cups water with 20ml salt. Bring to the boil and pour over the lemon grass stalks. Seal and store in the refrigerator. Use as required.

No nuts please

Q My son is allergic to nuts. Can I just leave them out of a recipe? - Susan Rawkins

A For most recipes, you can, but if they are a feature of a recipe I suggest you replace them with seeds, such as poppy, sunflower or pumpkin, or a mixture of the three. If you are making something savoury, I would replace the nuts with fried mushrooms, which would provide the texture of a cooked nut.

Cake tins

Q I have been asked to make a round Christening cake and I only have a square pan. How do I convert and know if my pan will be okay for the recipe? - Emily Jones

A There is a standard formula: use a square tin that is 2-3cm smaller than the round tin required. For instance, if your recipe calls for a 20cm round pan, the same amount of mixture will fit into an 18cm square one.