Preheat oven to 375 degrees F. Spray 1 1/2-quart casserole dish with cooking spray; set aside
Blanch spinach. Squeeze excess water.
In a medium bowl, mix together spinach, garlic and lemon zest. Add artichoke hearts, 1-cup Parmesan, sour cream, mayonnaise and cayenne pepper sauce. Mix. Place into prepared casserole dish. Bake for 30 minutes. The last 5 minutes add the remaining 1/2 cup of Parmesan to the top. Serve hot or cold along with pita chips.