Parmesan Arugula Dumplings

Name: Parmesan Arugula Dumplings
Ingredients: 1 tablespoon extra-virgin olive oil; 1/2 cup minced white onions; 2 medium garlic cloves, thinly sliced; Salt and freshly ground black pepper; 1 (28 ounce) can diced tomatoes with juices; 1/2 teaspoon granulated sugar, optional; 8 ounces baby arugula; 1/2 cup whole milk; 2 large eggs; 4 ounces day-old crustless French or white bread, finely chopped; 3/4 cup grated Parmesan; 1 to 2 teaspoons kosher salt; 1/2 cup all-purpose flour; 1/8 teaspoon freshly ground nutmeg; 1 cup shredded mozzarella