Preheat oven to 350ºF. Coat a 7 1/2-inch deep-dish glass or ceramic pie plate (or oval oven-proof dish) with cooking spray.
In a food processor, combine spinach, artichokes hearts, garlic, red pepper flakes, salt, Parmesan cheese, sour cream and cream cheese; puree until smooth. Using a spatula, scrape dip into prepared dish; smooth top into an even layer. Bake until golden on top, about 20 to 30 minutes, depending on desired doneness. Serve warm. Yields about 1/4 cup per serving.
Notes
If your food processor isn’t big enough to accommodate the spinach, either chop the spinach roughly or work in batches.*If you don’t have fresh spinach on hand, try frozen.