Asparagus, olive and cheese frittata

I must conduct an experiment sometime to test the truth of the frequent assertion that green vegetables, if they are to retain their colour, should be cooked in plenty of boiling water in an uncovered pan. The theory is good: acidity is what turns asparagus, broccoli and the rest an unappetising khaki, and acidity increases in a covered pan. Chefs also advise you to plunge the cooked vegetables into iced water, to "fix" the colour. But both these procedures -- boiling in a copious quantity of water, and refreshing the vegetables -- lose more nutrients than would steaming. Maybe it is better to put up with grey-green vegetables. We are trying to feed ourselves, not win Michelin stars.

For this frittata, for three, I used six eggs. But I think it would have been better to follow my previous advice and use five. The longer the frittata cooks, the tougher it will be. I also threw on the cheese towards the end -- and that was an improvement. It needs only to melt, rather than to cook with the egg.

5 eggs, lightly beaten
Knob of butter
60g hard cheese (I used Cheddar)
Bunch of asparagus
Handful of pitted black olives (I like the Crespo Greek-style ones)

Melt the butter over a very gentle heat to coat a heavy, 28cm frying pan. Pour in the eggs.

Meanwhile, bring a pan with an inch or so of water to the boil. Cut off and discard the tough ends of the asparagus, throw the stalks into the pan, and simmer for a couple of minutes, until tender when pierced by a knife. Drain, and cut into fork-sized pieces. Stone the olives, if necessary.

When the bottom of the omelette is set, but with a runny surface, scatter over the cheese, asparagus, and olives. Finish cooking for a minute or so under a low grill.

Cut into wedges, and serve hot or cold.