Spinach, Sausage, and Feta Frittata

This is Kyle's absolute favorite breakfast.  This past summer, he requested it for his birthday breakfast.  Well, we were camping.  So we managed to pull it off in a dutch oven.  Tasted even better on a chilly mountain morning.

1 T oil
1 medium onion, chopped
10 oz baby spinach
1/4 cup sun-died tomatoes in oil, drained and chopped
4 links fully-cooked chicken sausage, sliced (Alfresco and Aidells both have some really yummy flavors)
8 eggs
4 oz fat free crumbled feta (Trader Joes) (or regular feta)

Preheat oven to 350.  Using a large, flat pan that can go in the oven, saute the onion for 5 minutes on medium to medium-high heat.  Add sliced sausage, saute 3 minutes.  Add spinach and sun-dried tomatoes, saute 2 minutes.  Whisk eggs.  Pour over sausage mixture, stir.  Top with feta.  Cover.  Cook in oven for 5-8 minutes or until set in middle.  Enjoy!