Preheat your oven to 350 degrees F. Crack your eggs into a small mixing bowl. Grate your Parmesan and Romano and crumble your feta, if needed. Toss the cheeses together in a small bowl.
Heat a 12-inch cast iron or oven-safe skillet on the stove over medium-high heat. (If using a cast iron, the handle will get hot, so protect your hand with a glove or oven mitt.) Add your olive oil to the pan and spread it around to cover the bottom.
Use a garlic press to press your garlic into the pan. (Or chop it finely, if you don't have a press.) Stir the garlic around for about 30 seconds.
Add your arugula to the pan and stir to coat the greens with the oil. Sauté the arugula for at least five minutes, until wilted.
While the arugula is cooking, beat your eggs with a whisk or fork. Stir in your black pepper and sprinkle of salt.
When the arugula is completely wilted, pour your eggs over the top. Sprinkle on your cheese in an even layer, covering the entire surface. Turn off the heat on the stove.
Place your pan in the oven on the center rack. Bake for 15 minutes, then broil for three minutes to lightly brown the top.
Cut the frittata into wedges to serve, and sprinkle extra Parmesan on top, if desired.
To make this completely on the stove, lower the heat when you add your eggs and cheese to the pan. Cook the frittata on low until the top is almost completely set, with just a small circle in the middle that needs to cook more. Flip over the frittata: If you don't have a special frittata pan, you will need to invert the frittata onto a round platter or pizza pan, then flip it again onto another round platter, then invert it back into your skillet. Cook until the bottom is done.