Heat olive oil in a 12" or larger sauté pan or skillet on medium heat until hot, then add onions and garlic. Cook until lightly golden and tender, 5-8 minutes.
As onions are cooking, cook pasta per package directions in boiling, salted water until just done (for me, this was about 8-9 minutes of cook time.) Drain but don't rinse pasta.
Add spinach, sun dried tomatoes, vodka sauce, Italian seasoning, and light cream to skillet. Turn heat to low and let simmer until warmed though, about 10 minutes.
Add pasta to sauce and stir to coat. Add 1 cup of mozzarella and 1/4 cup of Parmesan cheese, stir. Season with salt and pepper to taste.
Transfer pasta into a large baking dish and top with remaining mozzarella and Parmesan. Bake at 400 degrees for approximately 25-30 minutes or until brown and bubbly. Serve hot with garlic bread.