Peel and cut the potatoes into evenly sized chunks
Boil the potatoes in salted water for 15–20 minutes, or until fork tender.
Drain well and mash until smooth. Let them cool slightly.
Mix the mashed potatoes with Parmesan, eggs, parsley, garlic, salt, pepper, and nutmeg until well combined.
Take about 2 tablespoons of the mixture and flatten it in your hand.
Place a cube of mozzarella in the center and shape into an oval croquette, sealing the cheese inside.
Roll each crocchetta in flour, dip into beaten egg, and coat evenly with breadcrumbs.
Arrange the crocchette on a tray and rest for 30 minutes in the refrigerator to help them firm up.
Heat vegetable oil to 350°F (175°C).
Fry the crocchette in batches for 3–4 minutes, turning occasionally until golden brown and crispy.
Transfer to a paper towel-lined plate to drain.
Serve hot with marinara sauce, garlic aioli, or your favorite dipping sauce.