Preheat oven to 400°F. Coat a 12 cup muffin tin ( or 6 cup jumbo size muffin tin) with non-stick spray. Divide spinach, artichoke hearts, tomatoes and olive evenly between all muffin cups. Sprinkle with Feta cheese.
In a medium sized bowl, whisk the eggs, water, oregano (or Mediterranean/Italian spices)and salt and pepper. Pour egg mixture over the top of each muffin cup until just about full.
Bake for 20-25 minutes or until set ( Approx 20 mins for regular size muffin cups and about 25 mins. for jumbo muffin cups). Remove from oven and cool slightly before removing from muffin tin. Garnish with parsley and serve.