No votes for quiche? Rimmed Dutch oven ids will fit cast iron skillets as another way to bake pies as well as using a trivet inside a Dutch oven.
Karl, pay no attention to those who have no tastebuds nor imagination. I just have never made it in cast iron.
Quiche can contain ANY ingredients the heart/palate/stomach desires. Your pic of spinach quiche looks SOOOO good.
I cheat and make it in a 9" glass deep pie dish. I use Marie Callender's pre-made crust (excellent) but spray the glass with Baker's Joy (combination soybean oil and flour in a can) before placing the crust. (You will love me for that idea.)
Our usual combination is (in order of construction from bottom up): 1/2 lb. 1/2" cooked smoked ham pieces, 1/2 lb. crisp bacon crumbled, 2 cups frozen broccoli florets, 3/4 cup shredded Swiss cheese, 1/4 cup shredded cheddar cheese, 1 lb. sliced, fresh sautéed mushrooms in butter and GOOD garlic powder, then a mixture of 5-6 beaten whole fresh eggs (with 1/2 tsp salt and 1/4 tsp black pepper) scrambled with 1-1/2 cups heavy cream, then poured into the pie, and then another ample topping of shredded Swiss and Cheddar cheese to suit.
Bake
uncovered at 375* for 95 minutes and remove to cool/set for another 10 minutes.
YMMV, but we have used this recipe for decades. My wife calls it garbage pie, but eats twice what I do.
Feel free to modify to your palate's/heart's/stomach's content.
Jim