Mix beef, bread crumbs, eggs, milk and taco seasoning until just combined. Do not over mix.
Scoop out 4 tablespoons of beef mixture, flatten then place cheese cube into the center. Bring the edges together to form a ball. Ensure that the meatball is completely sealed.
Transfer meatballs to a greased rimmed baking sheet.
Freeze meatballs on baking sheet for 10-15 minutes to firm up.
Raise oven rack to top and preheat broiler on high.
Broil meatballs on high for 10-12 minutes or until cooked through. Some cheese may escape while broiling.