Slice potatoes thinly to 2mm thickness.
Combine the potatoes, olive oil, parmesan cheese, grain mustard, garlic, salt and pepper in a bowl and mix well with a spoon.
Pour some olive oil into muffin tins.
Place 2-3 potato slices in each muffin holder.
Then layer on the shredded cheese and prosciutto.
Repeat layering potatoes, cheese and prosciutto until ingredients are used up.
Top with rosemary and bake for 50 minutes at 190 degrees C.