Start by preheating the oven to 150°C.
Peel the potatoes, rinse, and dry then cut them into cubes.
Heat the milk with salt, the garlic clove, and the rosemary sprig.
Add the potatoes and cook for 15 minutes to soften them slightly. Remove the rosemary sprig, season with pepper and mix.
Cut the coppa slices into pieces and brown them without any fat in a frying pan.
Share out the potatoes and coppa between 4 glass jars.
Mix the cream and parmesan then pour over the potatoes that were previously placed there in jars.
Bake for 1 hour.