Fold in spinach, basil, sun-dried tomatoes, kalamata olives, and garlic. Fold in sourdough bread pieces, mozzarella cheese, and feta cheese, and transfer mixture to baking dish. Place baking dish on center rack of the oven and bake 45 minutes, or until edges are golden brown and the center is set. Allow to cool before slicing into pieces. Garnish with fresh basil and crushed red pepper if desired.
Cover and refrigerate up to four days.
This recipe originally appeared on GratefulGrazer.com.