Wash the potatoes well and cut them into cubes, keeping the skin on. Place them on a baking tray and season with a little olive oil, salt, pepper and sprigs of fresh rosemary.
Bake in a preheated oven at 200° for 1 hour.
Meanwhile, prepare the sun-dried tomato pate. Combine the dried tomatoes in oil, the clove of garlic, the capers and the basil leaves in a blender. Add a little olive oil, a pinch of salt and pepper. Blend everything until smooth.
Cut the Fontina AOC into not too thick slices by removing the rind and set aside.
Compose the sandwich, on the base make a layer of pate, arrange the spinach, baked potatoes, sliced mocetta and slices of Fontina AOC. Close the sandwich and serve.