Combine zucchini, yogurt, one (1) tbsp. finely chopped onion, 1/2 tsp. salt and 1/2 tsp. sugar.
Cover with plastic and refrigerate.
Heat oil in skillet, medium-high heat. Add one (1) c. onions and cook until clear.
Remove from heat and stir in curry and water until smooth, cool.
Heat oven to 375º. Combine turkey, zucchini, bread crumbs, egg, 3/4 tsp. salt and onion mixture and mix well.
Line a 13" X 9" pan with foil, coat bottom with cooking spray and shape turkey mixture into a 8" X 4" loaf.
Bake for 50 minutes, when done remove from oven and cover with foil, let stand ten (10) minutes.
Slice loaf, serve with yogurt sauce.