Classic Spaghetti and Meatballs

From America's Test Kitchen Season 2: Spaghetti and Meatball Supper

One of the problems with meatballs is that they’re thought of as smaller, rounder versions of hamburgers. This would be fine if meatballs were generally cooked to rare or medium-rare, as most hamburgers are, but meatballs are often cooked through till well-done. This can leave them flavorless, dry, and dense. As a result, they need some help to lighten their texture. What we were after was nothing short of great meatballs: crusty and dark brown on the outside, soft and moist on the inside.

White bread soaked in buttermilk is the best binder for meatballs, giving them a creamy texture and an appealing tang. Eggs are also important for texture and flavor; their fats and emulsifiers add moistness and richness. Egg yolks alone work best and keep meatballs moist and light; the whites just make the mixture sticky and hard to handle, with no other added benefits. Adding some ground pork to the usual ground beef enhanced the flavor; we found 1 part pork to 3 parts beef to be about right. Pan-frying (as opposed to broiling, which dried out the meatballs) was the best way to brown the meatballs and kept the interior moist. Finally, building the tomato sauce on top of the browned bits left in the pan after frying the meatballs made for a hearty, robust-tasting sauce.