• Recipe: double chocolate olive oil cake

I find that cakes made with oil are always moist. Can I substitute oil for butter in any cake? B. Warner

Yes and no. When a recipe requires the butter and sugar to be creamed together until light and fluffy you are trapping little air bubbles in the butter that will expand and make the cake rise. Oil doesn't do this. So "light and fluffy" butter means no to using oil. Where you have a recipe for a muffin that uses melted butter it is perfectly OK to use a light olive oil or vegetable oil. Because butter is around 15 per cent water you will need to use roughly 15 per cent less oil to match the fat content. You may need to add a splash of milk or similar to make sure the flour has enough liquid to hydrate properly.

Can you get food poisoning from eating reheated rice? H. O'Grady

Reheated rice can be dangerous. There is a bacteria called Bacteria cereus that can occur naturally on rice. It is incredibly hardy and not only persists the dry conditions in a packet of rice it can even survive the cooking process. After cooking, the warm moist rice provides the perfect environment for the bacteria to breed and produce a toxin that makes you sick and can lead to liver failure. If a rice cooker sits around on the bench for a few hours the bacteria can show more reproductive behaviour than schoolies week at Surfers. To be on the safe side, cool rice for later use as quickly as possible. Keep rice in the fridge for no more than one day until reheating, reheat rice until steaming all the way through and do not reheat rice more than once.

Will adding oil to the pasta pot stop my spaghetti from sticking? L. Mellor

Olive oil can help untangle unmanageable hair, assist a nail to penetrate hardwood and add hours of fun to blow-up pools for some high-profile British businessmen alluded to in the British tabloids. It won't however, stop pasta from sticking together. Cooking pasta doesn't need lubrication; it requires agitation. When the pasta hits the boiling water the starch begins to swell and gelatinise. Some of the starch leaches out from the pasta and forms a sticky surface layer. Left alone, pasta will naturally clump together. But stir the pot well several times in the first few minutes or so after adding it to the pot and the pasta pieces will separate. What olive oil does do, is help stop the pot from boiling over. The starch from the pasta helps form bubbles that create a raft with each new bubble forcing the ones on top further up until they overflow. The addition of a little oil, will break the surface tension of the water stopping the bubbles from forming. Oil or no oil remember that the starch in the pasta water will help emulsify the sauce – stir a few tablespoons through a simmering sauce just before adding the pasta.

Email your questions to Richard at brainfood@richardcornish.com.au