White sauce is quite dreadful - it's the culinary equivalent of wallpaper paste. Nasty, glutinous and devoid of taste. But it does have one big plus despite its drawbacks: it's the base for a lot of sauces that are good to eat. It's worth knowing how to make a white sauce simply so that you can convert it easily into something nice.

All the recipe books I've ever seen tell you to start with a walnut-sized knob of butter and some flour. Any time I've done this, I've ended up with a lumpy sauce that needed to go through a sieve. Maybe this is why packet sauce is available - people have tried to make it, failed like I did, and now buy it in a packet.

I don't know if it's original, but for a while now I've been making it my own way; it's easy and it works every time. For a perfect white sauce with no lumps take a small saucepan and cover the bottom with olive oil. Add two heaped desertspoonfuls of flour and stir well with a wooden spoon. This will end up the colour and texture of runny fudge. Add half a litre of cold milk and stir, then put it on a high heat. Start stirring at once, and keep stirring gently until the sauce boils and thickens in five minutes or so. Remove it from the heat, salt it, and it's done - lump-free white sauce ready to become something else. Classic white sauce is made with water not milk; milk is already an improvement on the original.

Add pepper and grated nutmeg and it's a bechamel, ready to layer in a lasagna. Add cream and some tomato puree and it's a sauce aurore. Grate in cheese, put it back on the heat stirring all the while until it melts, and it's a cheese sauce for boiled vegetables, macaroni cheese or Welsh rarebit. Stir in curry powder and it becomes a curry sauce. Versatile, quick and cheap, white sauce may have little to commend it as it stands, but it's a building block for better things.