Polpette di manzo toscane in salsa di pomodoro

Remove skin from boiled potato, mash potato in small bowl and discard skin.  Remove outer layer from Tuscan sausage, so you're working only with meaty interior.  

In a medium mixing bowl, blend ground beef, skinned sausage, the mashed potato, egg yolk, grated Parmesan cheese.  Add small amount of salt and freshly ground black pepper to your liking.  

When the meat mixture is well-blended, shape into 8 medium-large meatballs.    

Peel and finely mince yellow onion half, set aside.  Peel and finely mince garlic clove, set aside. Wash and dry parsely, finely mince and set aside.

In medium sauce pan with deep side, coat bottom with extra-virgin olive oil.  Add minced garlic, onion and parsely and bring everything to sizzling over medium-low heat.  Add canned tomato, adjust to taste with salt and add shaped beef meatballs into tomato sauce.    

Don't mix meatballs in tomato sauce for at least 5-6 minutes (if necessary, lower flame just a bit so meatballs don't stick to bottom of sauce pan).  

After first 5 minutes, using two soup spoons, gently turn over each meatball to other side.  Cover pan and cook over low-medium flame for between 50 minutes to 1 hour.  

Serve beef meatballs promptly in individual serving plates with generous amount of tomato sauce to accopmany the meatballs.