1. Preheat oven to 400°.
2. Coat a 2-quart soufflé dish with baking spray.
3. Combine 1/4 cup milk and flour, stirring with a whisk. Bring flour mixture and 2 2/3 cups water to a boil in a medium saucepan; simmer 2 minutes. Remove from heat; stir in remaining 1 cup milk and potato flakes. Add yogurt and remaining ingredients, stirring until just combined. Spoon into prepared dish. Bake at 400° for 45 minutes or until puffy.
4. Turn on broiler (leave dish in oven). Broil 2 minutes or until lightly browned. Serve immediately.