Chop the onions and sauté them with oil in a cast iron, ceramic or stainless steel pan on the stove on medium heat, until soft.
Chop the vegetables into bite-size pieces and add them to the cooked onions along with a pinch of real salt. Continue to stir the vegetables for even cooking for about 10 minutes, or until tender. If you are using leafy greens add them towards the end and continue to cook until they are wilted. Remove from heat and allow to cool. You can also just use leftover vegetables that are already cooked.
Crack each egg into a small bowl one at a time and then add it to a large bowl. This will prevent a spoiled egg from ruining the whole batch. Beat the eggs with the salt, pepper, herbs and garlic.
Add the cooked vegetables and onions to the egg mixture. Oil a Pyrex type baking pan or cast iron skillet with oil. Add the egg mixture to the baking pan, keeping in mind that the frittata may rise about an inch.
As an extra flavor and nutritional boost, you can store in sliced sausages or other meat and/ or bake with grated cheese topping.
Bake at 350°F for about 30 - 40 minutes, until you can insert a toothpick or butter knife in the center and it comes out clean. A thicker frittata takes longer to cook. If adding pesto, slather some on your frittata once it is done cooking and cooling on the counter.
Frittatas are great fresh out of the oven or reheated later for a fast, convenient breakfast or snack.
