Preheat the oven to 350°F (175°C) if baking.
Prepare ingredients: drain and chop the artichoke hearts, thaw and thoroughly drain or squeeze excess moisture from frozen spinach if using, and soften the cream cheese.
In a mixing bowl, combine the softened cream cheese, mayonnaise (or sour cream/Greek yogurt), 1½ cups grated Parmesan, mozzarella, chopped artichoke hearts, chopped spinach, and Stone House Seasoning. Mix until smooth and evenly combined.
Reserve 1/2 cup grated Parmesan for the topping, then transfer the mixture into a shallow baking dish (or into a 3-quart slow cooker if using).
If baking, sprinkle the reserved 1/2 cup Parmesan over the top and bake in the preheated oven for 20 minutes, until bubbly and lightly golden; serve warm with chips, crackers, or vegetables.
If using a slow cooker, cook on low for 2 hours or on high for 1 hour, checking occasionally to avoid overcooking; serve warm with chips, crackers, or vegetables.