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 1/2 cup water and ground meat to skillet with the onions and celery. Season with Break meat apart and cook until no pink remains and water has evaporated.
Add contents of small bowl to skillet mixture and stir to combine thoroughly.
Reduce heat to Low, cover skillet, and simmer 5 - 10 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.