Make sure that all your ingredients are at room temperature before starting.
Juice the lemon.
Place the egg yolk, Dijon mustard, salt, pepper and lemon juice in a mixing bowl, and whisk together until smooth.
While continuously whisking, slowly drizzle in the sunflower oil.
If the mayonnaise is too thin, add more oil.
Should the mayonnaise split (look curdled), do not throw it away. You can rescue a split mayonnaise, by placing a teaspoon of mustard in a clean mixing bowl, whisking it vigorously while drizzling in the split sauce.
If it is too thick, you can add more lemon juice or vinegar if the mayonnaise also lacks acidity, or you can add some water if it is tart enough.
Adjust the seasoning if necessary.
The mayonnaise will keep in the refrigerator for about three days.
Pick the leaves and finely slice the dill and parsley
Roughly chop the capers.
Finely dice the gherkins.
Fold through the mayonnaise.
«If the mayonnaise 'splits' Start with a clean bowl, add a teaspoon of boiling water. Then proceed to slowly add the 'split' mayonnaise mix back into the water a little at a time while whisking vigorously.»