In a small bowl, mix together ketchup, brown sugar, Worcestershire sauce, cocoa powder, salt, Sriracha, basil, oregano, fennel seeds, and paprika. Set aside.
Melt butter in a large, heavy skillet over medium heat. Increase heat to medium-high and add chopped onions and celery. Stir intermittently until the onions just begin to brown.
Add ½ cup water and ground meat to skillet with the onions and celery. Break meat apart and cook until no pink remains and water has evaporated.
Add grated carrots and contents of the small bowl to skillet mixture and stir to combine thoroughly.
Reduce heat to Low, cover skillet, and simmer 10-15 minutes.If mix is too thick: Add up to a cup of water before simmering (Don't go crazy, though!)
To thicken the mixture, add 2 - 4 tablespoons of quick or old-fashioned oats. This works best if you run them through a food mill or small blender first. Be careful though - you don't want to turn it into oat flour - you just want to break the oats up a little.
Assemble Sloppy Joes immediately before serving.
SLOW COOKER DIRECTIONS: Do steps 1 - 4 as outlined, then dump everything into the slow cooker, and cook on low for 1-2 hours.INGREDIENT NOTES:
BROWN SUGAR: If you prefer your Joes a little less sweet, reduce or omit the brown sugar according to your tastes. Also, pay attention to the amount of sugar in your ketchup - if it is a very sweet variety, you will want to cut back on the brown sugar.
CHEESE: I usually use cheddar, or a blend of cheddar and jack. Just use whatever sounds good to you.