Prepare Alessi Risotto Alla Milanese per package directions. Let risotto come to room temperature then transfer to refrigerator to chill overnight, or until cold (about 1 hour).
Meanwhile, brown 4 tablespoons of butter in a large skillet over medium heat. Lightly whisk butter until it achieves a deep golden hue. Stir in chopped sage leaves, followed by butternut squash cubes. Generously season with pepper and salt, to taste. Cover and cook squash for 15-20 minutes or until tender, flipping squash occasionally. Transfer butternut squash to a plate and set aside to cool.
In same large skillet, bring ½ inch* of vegetable oil to 350F. *Actual amount depends on size of pan.
Place flour, whisked egg and bread crumbs in three separate bowls. Work in batches to form arancini using 2 tablespoons of risotto per ball. Enclose one mozzarella pearl and one piece of cooked butternut squash in center of each ball. Roll each ball in flour, then egg and lastly, bread crumbs. Repeat until 10 arancini are formed.
Fry arancini until golden brown, about 5 minutes, being sure to rotate throughout cooking. Remove from frying pan and season with salt.
Garnish with freshly grated Pecorino Romano cheese and parsley. Serve with Alessi Marinara.