Add tomato paste, water, monk fruit sweetener, apple cider vinegar, salt, and spices to a medium size pot.
Mix well and simmer the ketchup over low heat for 30 minutes with a lid on the pan. Make sure you stir the ketchup every 5 minutes.
Remove lid and let it cook another 15 minutes.
To make the homemade sugar-free ketchup smooth and creamy, blend it or use a hand blender for 30 seconds on high.
Allow the ketchup to cool and store in the fridge for 3 weeks or freeze for 6 months.
The favor of the ketchup will get better the second day.