Spray medium skillet with cooking spray; heat over medium heat. Add mushrooms, dill weed, lemon juice and pepper; mix well. Cook 6 minutes or until mushrooms are tender, stirring frequently. Remove from skillet; cover to keep warm.
Pour Egg Beaters into skillet. Cook over medium heat 6 minutes or until almost set in center. Then carefully push cooked Egg Beaters to center of skillet with spatula and tilting skillet as necessary to allow uncooked portion to flow underneath. Remove from heat.
Preheat broiler. Place muffin halves, cut-side up, on rack on broiler pan; top each with slice of bacon. Cover each with equal portions of cooked Egg Beaters and cheese. Place under broiler 1-1/2 minutes or until cheese melts and begins to brown.
Sprinkle top of each sandwich with cooked mushrooms and green onions. Serve immediately.