Sauté sliced onion in hot oil in a large saucepan over medium-high heat until tender. Add potato, carrot, and 1/4 cup water; cook, stirring constantly, 2 minutes. Add leeks and spinach, and cook 3 minutes or until spinach wilts.
Whisk together vegetable broth and flour until smooth. Stir broth mixture, minced parsley, soy sauce, and salt into spinach mixture. Bring to a boil; cook, stirring constantly, 1 minute. Reduce heat to low; cook, stirring often, 5 minutes or until thickened.
Spoon vegetable mixture into a lightly greased 8-inch baking dish. Drop Cornbread Topping by heaping tablespoonfuls onto hot vegetable mixture.
Bake at 400° for 30 minutes or until golden.
*Chopped kale, collard greens, or turnip greens may be substituted.