Preheat oven to 350 degrees. Preheat nonstick skillet over high heat for one minute.
Remove from heat, spray with olive oil spray, then return to stove. Add onions, and
reduce heat to medium-high.
Cook for 30 seconds, then add mushrooms, and cook for 30 more seconds. Add broccoli
and sausage, cook for 30 to 60 seconds more. Let cool slightly.
Spray six portions of a muffin tin with olive oil spray. Stir together egg whites,
vegetable and sausage mixture, feta cheese, green onions, sea salt, and black pepper.
Pour into six tins.
Bake for 18 to 20 minutes or until casseroles are set.