Dump the sardines and their oil in the bowl of a food processor, along with the butter, shallot, and lemon juice, and process until smooth. Add 2 tablespoons of the herbs and pulse 2 or 3 times.
Pack the pâté into a small ramekin (or back into the sardine cans). Smooth with a spatula, then top with the remaining 1 tablespoon hers. Wrap tightly in plastic wrap and refrigerate for at least 1 hour to firm the texture.
