Step-by-Step Instructions:

Prepare the Meat and Filling:

Lay the beef slices on a cutting board and pound them thin with a meat mallet.

In a bowl, mix ground beef, breadcrumbs, grated cheese, parsley, salt, and pepper.

Assemble the Roll:

Spread the filling evenly over the thin beef slices.

Add hard-boiled eggs, mortadella, and diced cheese along the center.

Carefully roll the beef tightly and secure with kitchen twine or toothpicks.

Brown the Roll:

Heat olive oil in a skillet. Sear the meat roll on all sides until browned, then set aside.

Prepare the Sauce:

In the same skillet, sauté onion, carrot, and celery in olive oil until softened.

Add the tomato purée and cook for a few minutes.

Simmer the Bruciuluni:

Place the browned roll into the sauce. Cover and simmer over low heat for 1 hour, turning occasionally.

Serve:

Slice the roll into rounds, arrange on a serving platter, and spoon the rich sauce over each piece.

Variations and Tips:

Cheese Options: Substitute caciocavallo with mozzarella or any semi-hard cheese.

Dietary Substitutions: Use plant-based ground meat and cheese for a vegetarian twist. Replace eggs with cooked lentils for extra protein.

Cooking Tip: Ensure the meat roll is tightly secured to prevent the filling from spilling out during cooking.