"This is my grandmother's recipe for meatballs. It's very quick and easy, and they come out very tasty. They can be served with spaghetti, or as meatball subs, or any way you'd like to serve meatballs."
Mix ground beef, bread crumbs, egg, onion, black pepper, nutmeg, and salt together in a bowl; form into small balls. Arrange balls on a baking sheet.
Bake in the preheated oven for 10 minutes. Flip meatballs and continue baking until cooked through, 12 to 15 minutes. An instant-read thermometer inserted into the center should read at least 160 degrees F (70 degrees C).