This recipe is adapted from Delia's Complete How To Cook
| 2 large eggs, separated|
| 1 dessertspoon lemon juice|
| 1 dessertspoon white wine vinegar|
| 110g block butter, softened|
| Salt and freshly ground black pepper|
|Equipment: You will need a small food processor with a feeding hole in the lid, or an electric hand whisk or balloon whisk.|
To begin place the egg yolks (see our Video Techniques lesson on how to separate eggs), in a small food processor or blender and add some seasoning.
Then heat the lemon juice and white wine vinegar in a small saucepan until the mixture starts to bubble and simmer.
Now pour the hot lemon juice mixture in to join the yolks and blend for 30 seconds until thoroughly combined.
Then, using the same saucepan, melt the butter over a gentle heat, being very careful not to let it brown. (If your processor lid has a larger feeding hole, cover it with a piece of cling film to prevent the sauce splashing).
When the butter is foaming, switch the processor or blender on once more and pour in the butter in a thin, slow, steady trickle; the slower you add it the better.
(If it helps you to use a jug and not pour from the saucepan, warm a jug with boiling water, discard the boiling water and then pour the butter mixture into that first.)
When all the butter has been incorporated, wipe around the sides of the processor bowl or blender with a spatula to incorporate all the sauce, you should end up with a lovely, smooth, thick, buttery sauce.
To make the Hollandaise into Foaming Hollandaise:
Whisk the remaining 2 egg whites to soft peaks in a large clean mixing bowl and fold into the sauce immediately. This makes the sauce lighter and it goes further.
Note: this recipe contains raw eggs. It can be kept in the fridge then reheated in a bowl over a pan of gently simmering water or you can even make it ahead and freeze it.