Preheat the oven to 200°C, fan 180°C, gas 6. Prick the baking potatoes all over with a fork and place in the oven for 1 hour.
Meanwhile, in a food processor, whizz together the sardines, cream cheese and lemon juice until the mixture is smooth and there are no bones.
When the potatoes are ready, cut open and divide the pâté among them. Serve immediately with the salad.