Pour both cans of crushed tomatoes into your slow cooker.

Swirl about ¼ cup water in each emptied can, then add that liquid to the cooker.

Add sugar, apple cider vinegar, onion powder, garlic powder, salt, celery salt, mustard powder, black pepper, cayenne pepper, and the whole clove.

Whisk all ingredients until evenly combined.

Cover and cook on LOW for 12 hours, stirring once halfway through to prevent sticking.

After cooking, remove the clove. Blend the mixture with an immersion blender for a super smooth ketchup—or leave it slightly chunky for rustic charm.

Let cool slightly, then transfer to sterilized jars and chill. The ketchup will thicken as it cools.