HEAT oil in small nonstick skillet on medium-high heat. Add mushrooms; cook and stir 2 min.
ADD eggs and pepper; cook 2 to 3 min. or until eggs are almost set, lifting edge with spatula and tilting skillet to allow uncooked portion to flow underneath. When egg mixture is set but top is still slightly moist, top omelet with small spoonfuls of reduced-fat cream cheese.
SLIP spatula underneath omelet, tip skillet to loosen and gently fold omelet in half. Slide or flip omelet onto serving plate.