Quick and Easy Tomato Ketchup (Slow Cooker)

In a blender or food processor, combine the tomatoes, onion, shallot, vinegar, brown sugar, mustard, allspice, cinnamon, mace, ginger, cloves, and red pepper flakes. Blend until puréed.
One 28-ounce carton or can of chopped tomatoes, 1 small sweet onion, 1 medium shallot, ½ cup cider vinegar, ¼ cup light brown sugar, ½ teaspoon dry mustard, ¼ teaspoon ground allspice, ¼ teaspoon ground cinnamon, ¼ teaspoon ground mace, ¼ teaspoon ground ginger, ¼ teaspoon ground cloves, ¼ teaspoon ground red pepper flakes
Pour the mixture into the slow cooker.
Cover and cook on HIGH for about 2-1/2 hours. Stir and scrape down the sides every 30 minutes or so.
Remove the lid and continue to cook the ketchup on HIGH, stirring and scraping down the sides regularly, for about another hour or until the ketchup is the consistency you want.
Season with salt and pepper to taste, stir, then turn off the slow cooker and let the ketchup cool to room temperature in the pot.
¼ teaspoon sea salt, freshly ground pepper
Scrape into a glass jar for easy storage.