Ensure that the spinach is completely thawed. Squeeze out any excess moisture. (spinach holds a lot of moisture so make sure to squeeze out the excess so your dip isn’t watery as it cooks)
Drain the canned artichoke hearts and chop them into smaller bite-sized pieces.
Lightly grease the inside of the Crock Pot with olive oil to prevent sticking.
*Most recipes say to just throw in softened cream cheese cut into pieces but I found that those pieces, even when softened and small, don’t break down and mix in easily while cooking so you're left with pockets of cream cheese. I recommend melting your cream cheese in the microwave for about 15-20 seconds or until almost liquid, then adding it into your ingredients.
In a large mixing bowl, combine the spinach, chopped artichokes, mayonnaise, sour cream, Parmesan cheese, mozzarella cheese, cream cheese, minced garlic, salt, and black pepper.
Mix until all the ingredients are well incorporated.
Transfer the mixed ingredients into the greased Crock Pot, spreading it out evenly.
Cover the Crock Pot and cook on low for 2 to 3 hours. Check and stir occasionally to prevent burning or sticking at the edges.
If you prefer a spicier dip, stir in red chili flakes before serving.
Once the dip is hot and melty, give it a good stir and then serve it warm.