How to Make It
In a bowl, mix the lamb with the egg, bread crumbs and 1 tablespoon of the mint. Season with salt and pepper. Form the mixture into 1-inch balls.
Heat the olive oil in a very large skillet. Add the meatballs and fry over moderately high heat until browned all over, about 4 minutes. Transfer the meatballs to a plate.
Add the onion and garlic to the skillet and cook over moderate heat until softened, about 8 minutes. Add the wine and cook, stirring, until reduced by half, about 5 minutes. Transfer the mixture to a food processor. Add the remaining 1 tablespoon of mint and puree.
Return the onion puree to the skillet. Add the broth, tomato puree and meatballs and simmer over low heat until the meatballs are cooked through, about 10 minutes. Season with salt and pepper and serve.