Cheese and Cheese-less sun-dried tomato and spinach frittata

My family has a tradition of having alternating which years we have thanksgiving dinner at my parents' house with having it at my aunt and uncle's house. This year because it was at my parents' house we had brunch with my uncle, though I had offered to do the frittata, as I do love to cook, and why not.

I used 18 eggs for 12 people, though I could have done with 24. I simply mixed eggs, Lactaid milk, salt and pepper in a bowl and then divided into two. I then put in my sun dried tomatoes (not the kind that comes in oil, I find that the oil makes the eggs gooey in a bad way). I used cast iron pans as I find they do the best job with frittatas (and you can cut directly into the pan if you want, or easily transfer the entire frittata onto a serving platter if you want to be fancy about it), put them in the oven at 350* for about 20 minutes. Each oven is different, and because I have less experience using my uncle's oven, I checked the frittatas every 12 minutes or so.