In your slow cooker, add the broth, cauliflower, leeks, garlic, and pepper.
Cover and cook on low for 6-8 hours.
Then use and immersion blender to blend the soup or blend in a blender until smooth. If using a blender remember to not put the lid on tight. If you put the lid on tight with hot liquid inside a blender, you'll end up with a soup explosion! Also, if using the blender place soup back in crock pot after blending.
Add in the cheddar cheese and cream. Allow cheese to melt and stir until well blended. Add in the salt to taste.