In a food processor, combine chopped onion, garlic, parsley and bread crumbs. Process for 30 seconds.
Add egg to 3 quart bowl. Whisk to beat well.
Add water, olive oil, salt, pepper and nutmeg. Whisk until well mixed.
Add the bread crumb mixture to the egg mixture, combining with a spatula.
Add ground meat. Mix thoroughly until ingredients are well distributed and the mixture is binding together tightly.
Preheat oven to 425°F.
Lightly oil a jelly roll pan.
Using a medium sized ice cream scoop, scoop, scoop out a portion of the meat mixture.
Form a meatballs by rolling scooped meat mixture in the palm of your hand until they feel tight and solid. The finished meatballs should be about the size of a golf ball.
Place shaped meatball onto the oiled jelly roll pan.
Pour 1/4 cup water into pan.
Place pan in preheated oven. Cook for 15 minutes.
Remove from oven and loosen meatballs with a spatula.
Return to oven an additional 10 minutes, or until cooked through.
Remove from oven. Remove meatballs to a paper towel-covered plate to drain.
Prepare pasta according to package directions. Drain. Set aside.
Pour tomato sauce in a large skillet.
Place skillet over medium heat.
Add the meatballs. Simmer for 2 minutes or until heated through.
Pour pasta over spaghetti or serve separately and allow guests to serve themselves.
Serve hot.