Preheat oven to 350 degrees (325 degrees if using glass pan). In large bowl mix egg white, vanilla and yogurt. Stir in brownie mix and stir until jut blended. Mixture will be very thick. Spray 9x13x2 pan with nonstick cooking spray and spread mixture in pan. Bake at 350 degrees for 20-22 minutes, watching carefully not to overbake. Let coo] at least 2 hours before cutting in 24 brownies. Each brownie equals 100 calories and 1.5 grams of fat.