Spray a skillet with cooking spray and heat to medium.
Add onion and cook for 8 minutes.
Add garlic and cook for one more minute.
Remove from heat and stir in cream cheese and milk until well combined.
Add artichokes, spinach, feta, parmesan, salt, and red pepper flakes.
Stir to combine.
Cover and cook on low for 3 hours.
Stir well.
Keep on warm to serve.
Instant Pot Dutch Oven
Spray the dutch oven with cooking spray. Set to Manual Mode 2 and set the temperature to 350° F.
Add the onion and cook for 8 minutes.
Stir in the garlic and hit cancel.
Add the cream cheese and milk and whisk until smooth.
Add artichokes, spinach, feta, parmesan, salt, and red pepper flakes.
Stir to combine.
Cover and cook on low for 3 hours.
Stir well.
Keep on warm to serve.
Notes
Storage
Leftover Artichoke Dip can be stored in an airtight container in the refrigerator. It should be eaten within 5 days.
Reheating
Just put the dip back in the slow cooker, set it to low, and let it get nice and hot again. I recommend stirring a few times to ensure it reheats evenly. You can also heat in a baking dish.