Preheat the oven to 400 degrees . In a bowl, moisten the bread with 1/3 cup chicken broth. Add the lamb, egg, garlic, 2 teaspoons salt and 1 teaspoon pepper. Form the mixture into 8 meatballs. Brush with EVOO and set 2 inches apart on a rimmed nonstick baking sheet. Roast for 15 minutes.
Meanwhile, in a medium saucepan, heat 1 tablespoon EVOO, 1 turn of the pan, over medium heat. Add the onion, season with salt and pepper and cook until softened, 8 to 10 minutes. Add the vinegar and cook it off, 1 minute. Stir in 2/3 cup chicken broth, then the tomatoes. Bring the sauce just to a boil, then lower the heat and simmer for 10 minutes.
In a medium saucepan, bring the remaining 2 cups chicken broth and the milk to a boil. Whisk in the polenta, lower the heat and cook, whisking, until the polenta is thick but spoonable, 2 to 3 minutes. Stir in the honey, butter, rosemary and salt and pepper to taste. If it gets too thick, add water or more milk.
Spoon the polenta into bowls; top with the meatballs and sauce.