Preheat oven to 400°. Place garlic cloves and chopped green onion in a food processor; process until chopped. Add Parmesan, mayonnaise, cream cheese, lemon juice, and crushed red ­pepper; process until almost smooth. Stir in artichoke hearts. Spoon mixture into a 3-cup gratin dish coated with cooking spray. Bake at 400° for 15 minutes.