Preheat oven to 350 degrees F
Spray a 9" tart pan or pie pan with non-stick cooking spray and set aside.
Dice onion and set aside; if using fresh broccoli, wash well and cut florets from stems.
In a large bowl, beat eggs, milk, salt, and pepper until fluffy.
Stir in cheddar cheese, onion, and broccoli.
Pour egg mixture into pan and sprinkle parsley on top.
Bake for 30-35 minutes or until eggs are set; allow to cool 5 minutes before serving.