Heat the coconut oil in a cast-iron skillet over medium-high heat. Add the red peppers and onions and saute until just beginning to turn translucent, 2 to 3 minutes. Add the ground beef, breaking it up with a wooden spoon. Saute until browned all the way through, about 5 minutes. (If using ground meat substitute, just heat until warmed through, about 2 minutes.)
In a medium bowl, whisk together the tomato paste, bourbon, soy sauce, cider vinegar, mustard, sorghum, cumin, liquid smoke, red pepper flakes and 1/2 cup water.
Stir the bourbon mixture and the garlic into the skillet. Simmer, covered, for 15 to 20 minutes. Season with more soy sauce as needed.
Toast the slider buns with a little butter in a cast-iron skillet over medium heat. Spoon the sloppy joe mixture onto the buns.