These were very yummy, easy, and my three-year-old loved helping make these! (I just had to watch closely to make sure he wasn't sticking his fingers in his mouth after touching the raw meat.) I got this from a free magazine that kraft sends out quarterly- you can get a subscription at www.kraftfoods.com.
1 lb lean ground beef
6 Ritz crackers, finely crushed
1/4 c grated Parmesan cheese
3/4 c spaghetti sauce, divided
about 12 cheddar cheese cubes (I cut up a block of cheese)
Preheat oven to 400 degrees. Mix meat, cracker crumbs, parmesan cheese and 1/4 c of the spaghetti sauce in bowl. Shape into 12 meatballs, using about 2 T meat mixture for each. Place 2 inches apart on a greased shallow baking pan that has been sprayed with cooking spray. Press 1 cheese cube deeply into center of each meatball. Bake 14 min. or until meatballs are cooked through (160 degrees). Meanwhile, microwave remaining spaghetti sauce to serve over top of meatballs. Enjoy!