1. Heat oil in medium skillet over medium-high heat. Add the 1 cup onions and cook 3 to 4 minutes or until lightly browned. Remove skillet from heat; stir in curry base and water until smooth. Cool.
2. For the Yogurt Sauce, combine zucchini, yogurt, the 1 tablespoon onion, the 1/2 teaspoon salt and the sugar in a medium bowl; cover with plastic wrap and refrigerate.
3. Heat oven to 375 degree F. Combine turkey, zucchini, bread crumbs, egg, the 3/4 teaspoon salt and the onion mixture in large bowl until just mixed. Line a 13x9-inch pan with foil; lightly coat bottom with vegetable cooking spray. Shape turkey mixture into an 8x4-inch-wide loaf in center of prepared pan. Bake 50 minutes or until internal temperature reaches 165 degree F.
4. Remove meatloaf from oven; cover with foil and let stand 10 minutes. Slice loaf and serve with Yogurt Sauce, and broccoli and red potatoes, if desired. Makes 4 servings.