Gather all ingredients. Drain and chop artichoke hearts. Thaw and drain frozen spinach to remove excess moisture.
In a large mixing bowl, combine softened cream cheese, sour cream, and milk. Mix until smooth and creamy.
Stir in chopped artichoke hearts, drained spinach, minced garlic (or garlic powder), onion powder, crushed red pepper, salt, and pepper. Mix evenly.
Fold in shredded mozzarella and grated parmesan cheese until fully combined.
Transfer the mixture to the crock pot and spread evenly. Cover with lid.
Cook on low for 2-3 hours or until hot and bubbly. Alternatively, cook on high for 1-1.5 hours, stirring occasionally.
Once cooked, stir the dip, adjust seasoning if needed, and serve warm with your favorite dippers like tortilla chips, fresh veggies, or toasted baguette slices.