For some reason, I only make frittatas for special occasions, like a holiday brunch or a bridal shower lunch. I've got to get more into them (and so should you) because they are absolutely delicious and very versatile. A frittata can be consumed at breakfast, lunch, or dinner, and can be filled with tons of ingredients. This recipe uses mustard greens, onions, and parmesan cheese. The flavorful combination of bitter greens and sweet onions work sublimely here. Instead of cooking it over the stove, I poured the egg mixture into a nine-by-13-inch pan that was lined with parchment paper; then I baked the whole thing in the oven like a crustless quiche. It was easier to slice into bite-sized portions and serve on toothpicks. However, if it was on the menu at a leisurely brunch, it would be fun to bring the saute pan to the table and let guests slice their own piece. This frittata would pair well with smoked salmon, roasted cherry tomatoes, or sparkling wine. To add a great frittata recipe to your rotation, keep reading.