Preheat oven to 350. Spray 13X9 inch glass baking dish with cooking spray.
Heat oil in large skillet. Add onion and garlic. Cook 2 minutes, stirring occasionally. Add spinach, artichokes, rosemary, and broth. Bring to a boil. Cook 10 minutes or until spinach is wilted.
Chop cauliflower. In a separate pot, boil cauliflower until soft.
Combine cooked cauliflower, parmesan, salt, and 1 c. of the spinach liquid in a blender. Process until smooth.
Add cauliflower mixture to spinach mixture. Stir well.
Spread 2 c. of the cauliflower mixture in the bottom of the prepared dish. Top with 3 noodles. Top with 1 c. mozzarella cheese. Repeat layers twice.
Finish with remaining cauliflower mixture, 1 c. mozzarella, and 4 oz. feta. Cover tightly with foil. Bake at 350 for 45 minutes.
Uncover, bake 15 minutes longer. Let stand 10 minutes before cutting.