Asparagus and foaming hollandaise sauce

Ingredients:

570g medium thick fresh asparagus
Salt

For the sauce:

2 large eggs, separated
1 dessert spoon lemon juice
1 dessert spoon white wine vinegar
110g salted Butter
Salt and freshly ground pepper
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You can make the sauce at any time, even chilling it overnight in the refrigerator, or you can serve it warm or even at room temperature.

Begin by placing the egg yolks in a food processor or blender together with some salt, switch on and blend them thoroughly. In a small saucepan heat the lemon juice and vinegar till the mixture simmers, then switch the processor on again and pour the hot liquid on to the egg yolks in a steady stream.

Switch off, then in the same saucepan melt the butter – not too fiercely: it mustn’t brown. When it is liquid and foaming, switch on the processor once more and pour in the butter, again in a steady, thin stream, until it is all incorporated and the sauce has thickened. Next, in a small bowl, whisk the egg whites until they form soft peaks and then fold the sauce, a tablespoon at a time, into the egg whites and taste to check the seasoning. When you’ve done that, it’s ready to serve or it can be left till later.

To cook the asparagus take each stalk in both hands and bend and snap off the woody end, then trim with a knife to make it neater. Lay the asparagus stalks on a steamer basket, they can be piled one on top of the other. Season with salt, place them in a frying pan or saucepan, pour in about 1 inch (2.5 cm) of boiling water from the kettle, then put a lid on and steam for 4-6 minutes.