3-4tablespoonsshredded fresh Parmesan Cheeseor other meltable cheese
Crack the 4 eggs to a bowl, season with a pinch of salt and pepper, and beat the eggs with a fork or a whisk.
Heat the olive oil in a 8 or 9-inch nonstick skillet, and add the diced onion. Cook over medium heat for 2-3 minutes, or until the onion softens. Add the torn kale leaves, and cook uncovered for 2-3 minutes. Season with salt & pepper, stir one more time, and cover with the lid to let the heat inside the pan cook down the kale leaves for 1 minute.
Lower the heat to the lowest it will go. Pour the eggs over the kale, and use a spatula to distribute the egg evenly all around the pan. If there are any kale leaves sticking out out of the eggs, just push them into the egg mixture, it's OK if a few pieces stick out.
Arrange the tomato slices on top of the eggs. Sprinkle with 3-4 tablespoons shredded Parmesan cheese. Cover with the lid and cook for about 5 minutes over low heat, or until the eggs are all fully cooked.
Remove from pan with a spatula, and slice into wedges. Serve as is, or try it in a breakfast sandwich!
You will need a skillet with a lid for this recipe. I recommend using an 8 or 9-inch nonstick skillet with a lid for this recipe. If your skillet is too large or too small, the frittata will be too thin or will not cook through.Serve this with a few crumbles of feta cheese or chopped green onion. Or enjoy it in a sandwich!Other frittata fillings that work great instead of kale: 3 cups baby spinach (cook for less time than kale), ½ - 1 cup finely diced bell pepper, cooked diced potato.