For the grappa potatoes:
While the mousse cools, boil the potatoes until nearly cooked through, cut in half, and scoop out most of the inside.
Mix the scooped out potatoes with 125g Grana Padano and the remaining ingredients to make a filling.
Fill the mixture into the hollow potatoes and sprinkle with 125g grated Grana Padano.
Cook in the oven at 180 ° C for about 15 minutes.