Preheat oven to 375°. In a large bowl, combine cream cheese and mayonnaise. Add artichokes, spinach, Parmesan, garlic, nutritional yeast, and 1 cup mozzarella; season with salt, black pepper, and red pepper flakes.
Transfer to a small baking dish and spread in an even layer. Top with remaining ½ cup mozzarella.
Bake dip until cheese is melty and filling is bubbling, about 30 minutes.
Serve warm with bread or crackers alongside.
