Open the can of sardines and drain well. We can save the oil for later. Next, with a fork, we crumble the sardines, one by one, to remove the central bone, which we will throw away.
Chop the onion and put the sardines, the chopped onion and, where appropriate, the chives or parsley in a food processor or the blender glass. Add a little lemon juice and the cream cheese, blending the whole until obtaining a homogeneous cream.
We taste and rectify salt and pepper and store it in a glass jar, leaving it in the fridge to take shape. If you are not going to eat it at the moment, you can cover the pâté with a little of the oil from the preserve that you had saved, to prevent the surface of the pâté from darkening and drying out.