Heat griddle or large skillet (if electric, heat to 350° F). Spray lightly with no-stick cooking spray. Combine egg, milk, oil and muffin mix in medium bowl; stir until large lumps disappear (batter will be slightly lumpy).
Pour about ¼ cup batter for each pancake onto hot griddle. Cook 1 to 2 minutes or until bubbles begin to break on surface. Turn, cook 1 to 2 minutes or until golden brown.
Spoon yogurt and berries on half of each pancake. Fold over. Sprinkle with powdered sugar, if desired.