01 -  Boil the cubed russet potatoes in salted water until fork-tender, about 12 to 15 minutes. Drain thoroughly and mash until smooth. Allow to cool slightly. 
 02 -  In a large mixing bowl, combine mashed potatoes, cooled white rice, shredded mozzarella, grated Parmesan, minced garlic, chopped parsley, dried oregano, dried thyme, 1 large egg, salt, and black pepper. Mix until the ingredients are fully incorporated. 
 03 -  Portion about 2 tablespoons of the mixture and roll into balls with your hands. Repeat until you have formed 16 uniform balls. 
 04 -  Arrange three shallow bowls: place all-purpose flour in one, beaten eggs in the second, and breadcrumbs in the third. 
 05 -  Roll each ball first in flour, then dip in beaten egg, and finally coat evenly with breadcrumbs. Transfer to a tray for frying. 
 06 -  Heat vegetable oil in a deep skillet or pot to 350°F. Fry the rice balls in batches for 3 to 4 minutes, turning occasionally, until golden brown and crispy. Drain on paper towels. 
 07 -  Arrange the hot rice balls on a platter and garnish with extra parsley if desired. Offer marinara or garlic aioli as dipping sauces.