Preheat oven to 300 degrees; coat a 9-inch pie plate with nonstick cooking spray. Combine cottage cheese, egg substitute, cream cheese, 1/2 cup sugar and vanilla extract in a blender container; cover and process until smooth. Pour mixture into prepared pan and bake for 35 minutes, or until edges are set. Combine yogurt, 1 tablespoon sugar and lemon juice; stir well. Spread evenly over cheesecake. Bake for an additional 5 minutes. Cool for 15 minutes. Cover and chill for at least 2 hours. Garnish with mint leaves, if desired. (146 calories, 3.1g fat, 19% calories from fat)