Combine bread and milk in a bowl, mashing to form a paste.

In a medium bowl, mix ground beef, ground pork, egg yolk, grated Parmesan, parsley, salt, and pepper.

Incorporate the bread and milk mixture into the meat mixture.

Form the mixture into approximately 15 meatballs, using about 3 tablespoons per meatball.

Heat vegetable oil in a frying pan over medium-high heat.

Add meatballs in a single layer, ensuring they don't overcrowd the pan.

Brown meatballs on all sides, turning frequently until cooked through.

Transfer browned meatballs to a paper towel-lined plate to drain excess oil.

Repeat the frying process with remaining meatballs if necessary.