In a large bowl, combine the mashed potatoes, shredded mozzarella, whipped ricotta, chopped marinated tomatoes, salt, and black pepper. Mix until well combined.

Form the Croquettes

Take a small amount of the potato mixture and shape it into a small oval or round patty. Repeat until all the mixture is shaped.

Prepare for Coating

Set up a breading station with flour, beaten egg, and breadcrumbs in separate bowls.

Coat the Croquettes

Dredge each croquette in flour, dip in beaten egg, and then coat with breadcrumbs. Ensure they are well covered.

Fry the Croquettes

Heat vegetable oil in a deep frying pan over medium heat. Fry the croquettes in batches until golden brown and crispy on all sides, about 3-4 minutes per side.

Drain and Serve

Remove the croquettes from the oil and drain on paper towels. Serve hot with your favorite dipping sauce or alongside a salad.