Meatball Sub

For 2 servings, use 300 g ground beef, 0.5 cup breadcrumbs, 1 egg, 2 garlic cloves, 300 ml tomato sauce, 120 g mozzarella, 2 sub rolls, and 1 tablespoon olive oil. Combine the beef, breadcrumbs, egg, and minced garlic. Mix with your fingertips only until the ingredients hold together, stopping before the meat becomes dense from heavy kneading. Divide the mixture into bite-size portions and shape round meatballs without packing them tightly. Smooth only their surfaces so the pieces cook at a similar rate. Heat the olive oil in a pan over medium heat. Add the meatballs and turn them gently until several sides are browned, leaving the centers slightly underdone for the sauce. Pour in the tomato sauce and lower the heat once it begins bubbling. Simmer for about 12 minutes, spooning sauce over the meatballs, until their centers are cooked and the sauce has thickened. Split and lightly warm the rolls. If the sauce still looks watery, reduce it a little longer before filling the bread. Add the meatballs and enough thick sauce, then divide the mozzarella over the top. Melt the cheese under a broiler or with a kitchen torch just until it blankets the meatballs. Serve immediately before the sauce softens the rolls.