This recipe for spinach feta oven frittata came about from my love affair with my cast iron skillet. This is a relatively new love affair, because I haven't had my cast iron skillet for all that long, so I am in the midst of doing all kinds of experimentation on the different things that come out deliciously in it, which so far is pretty much everything. From casseroles to cobblers, and from bacon to all kinds of eggs, this skillet is my new favorite kitchen buddy, and as your grandma could probably tell you, the more you use it, the more seasoned it gets, and the better it cooks. Obviously because of the whole cast iron thing, it can go from stovetop to oven, and it delivers a steady, serious heat that is perfect for things like frittatas full of cheese and spinach deliciousness. So grab your own cast iron skillet (or whatever oven-safe skillet you have - that will work too) and let's make it!