Set out a large 6-quart slow cooker. Turn on low heat. Drain the cans of artichoke hearts. Use your fingers to break the artichoke hearts apart into pieces. Then drain the thawed chopped spinach, squeezing by hand to omit as much water as possible.
Place the cream cheese, artichoke pieces, drained spinach, sour cream, mozzarella cheese, Parmesan cheese, milk, garlic, onion powder, crushed red pepper, 1 teaspoon of salt, and ½ teaspoon of cracked black pepper into the crock. Stir well to mix, then spread out in an even later. Use a damp paper towel to wipe the edges of the crockpot, so the dip residue doesn’t burn on the sides.
Cover the crockpot and cook on low heat for 2 to 4 hours until hot and molten. Then turn on warm and uncover when ready to serve.
Notes
For a much thicker dip, omit the milk. For a thinner dip, add a bit more milk.This recipe can also be baked in the oven in a 9 x 13 inch dish at 350°F for 20 to 25 minutes.Want to use an instant pot? You can either cook the dip on the sauté setting for 10 minutes, stirring regularly, or set on the slow cook setting for 2 to 3 hours as directed.Transfer the cooled dip to an airtight container and keep in the fridge for up to 3 days. Reheat in a microwave in short 20 second bursts at 50% powder. Stir between intervals of heating.