My chef mates roll their herbs in washed, moistened Chux and then cover with plastic film. If you're cooking with herbs, shortly after purchase you can pop them in a vase next to the bench to give that freshly food-styled feel to the kitchen.

If you're keeping them for longer, do the following: trim a few millimetres off the end of the stems with a very sharp knife as this helps the plant draw water up to the leaves. Remove the leaves from the stems as these will sully the water.

Keep your herbs in the fridge door and change the water every few days; this way you should be able to get a good week, maybe more, out of them.

Would you achieve the same result if you used spreadable butter in a recipe that calls for butter? N. Bannerman

Butter is made from cream and salt. Spreadable butter was a marketing solution for people complaining about hard butter. One popular brand of spreadable butter is made from cream, vegetable oil, water, butter oil, salt, buttermilk powder, an emulsifier called polyglycerol polyricinoleate, potassium sorbate, vitamins A and D and food colour.

You can achieve similar results in baking but be careful when creaming spreadable butter and sugar as the increased water content will make the sugar dissolve faster, which can affect the texture, making biscuits spread more.

When used for frying, the added solids in spreadable butter can brown faster and burn. The old-fashioned response to hard butter is to leave a little bit of butter in a covered butter dish at room temperature.

I was recently in northern Ireland and was eating a dish called ''champ''. What exactly is it and how do you make it? B. Sampson

Irish food is one of the most beautiful and honest cuisines on the planet - simple food, cooked well, and often involving potatoes. There's colcannon (potato and cabbage), boxty (a type of potato pancake), and coddle sausages baked with potato. Champ is basically mashed potatoes made with milk, butter and those long green onions that Victorians called ''spring onions'' and which New South Welshmen call ''shallots''.

So, take a bunch of spring onions/shallots, top and tail them, chop them (not too finely) and add them to a saucepan with a cup of milk. Bring to the boil then remove from the heat. Meanwhile peel, chop and boil a kilogram of potatoes, with a pinch of salt, until soft. Drain and roughly mash the spuds then add the milk and steeped shallots with a good pinch of salt and white pepper and whip with a fork with three tablespoons of good butter.

To give you an idea of the final consistency, ''champ'' is actually a Scottish word, which means to chop or mash. It also describes the consistency of ground trodden and mashed by the feet of farm animals.

I bake cakes fairly often but they don't seem to rise and are always cooked before the time specified by the recipe. I use a conventional oven. L. Murray

Ovens are funny beasts. They have hot and cold spots and most cook at temperatures that fluctuate around 10 degrees either side of the temperature on the thermostat.

Set the oven to 180C and the flame or element will stay on until the temperature reaches around 190C, then it will turn itself off, or down, and the temperature will drop to about 170C, meaning the average temperature is about 180C. Some ovens' thermostats have even less relationship with the number on the dial, giving you quite inaccurate temperatures in the oven. Yours sounds too hot.

You could test to see which temperature your oven operates at by dropping into a cookware store and picking up an oven thermometer - these cost $10 to $25 - and adjusting the setting using the knob until the oven thermometer displays the desired temperature.

If you find your oven is setting itself hotter than the temperature on the knob, call a service person. They should be able to get there the second Thursday in January.

If you have a vexing culinary query send it to brainfood@richardcornish.com.au