In a large, nonstick, covered skillet that has been lightly sprayed with cooking spray, cook onions and garlic over low heat until onions are soft, about 15 minutes. Uncover, stir in sugar, and continue to cook, stirring often, until onions begin to brown. Meanwhile, in a large saucepan, bring stock to a boil. Add potatoes, reduce heat to a simmer. Cook until potatoes are tender when pierced with a fork, about 15 minutes. Add onions. Add wine to skillet; stir to loosen any browned bits. Transfer wine mixture to potato mixture. Return to a simmer. Cook for another 5 to 10 minutes, until potatoes begin to fall apart and soup thickens. Stir in curry powder and dry mustard. Remove soup from stove; stir in yogurt. Return soup to stove; heat through. Do not allow to boil. Ladle into hot soup plates; with grated lemon zest and cucumber slices as garnish.
Servings: 8

NUTRITIONAL INFORMATION per serving: 137 calories; 4g protein; 30g carbohydrate; 1g fat; 45 mg sodium; 41 mg Cholesterol
Diabetic Exchanges: 2 bread/starch