1Heat 3/4 cup of the broth to boiling in 10-inch nonstick skillet over medium-high heat. Stir in onion, celery, cabbage, mushrooms, gingerroot, and garlic. Cook 5 to 8 minutes, stirring frequently and adding more broth if vegetables begin to stick, until vegetables are tender; remove from heat. Stir in soy sauce and sesame oil. Remove vegetable mixture from skillet. Wipe out skillet.
2Brush edges of 1 wonton skin with water. Place 1 heaping teaspoon vegetable mixture on center of skin. Fold skin in half over filling and pinch edges to seal. Make creases in sealed edges to form pleats on one side of each pot sticker. Repeat with remaining wonton skins and vegetable mixture.
3Spray skillet with cooking spray; heat skillet over medium heat. Cook pot stickers in skillet, pleated sides up, about 1 minute or until bottoms are light brown. Add remaining 3/4 cup broth. Cover and cook 5 to 8 minutes or until most of liquid is absorbed.