This sauce (and the companion Sweet and Sassy Spice Rub) makes next level barbecued chicken. It is also great on ribs, pork and hearty fish like salmon and catfish as well as Portobello mushrooms, charred onions and slabs of grilled potatoes! Make barbecued Portobello mushrooms at the same time as the chicken for the veggie lovers in your life.
In a large saucepan on the stove, add tomatoes, sugar, molasses, Bourbon, ketchup, chili sauce, vinegars, and Worcestershire sauce, stirring after each additional ingredient to combine. Add the Classic Spice Rub and simmer until flavors have blended and sauce has thickened somewhat, about 30 minutes.
Let the sauce cool for about 10 minutes or until it is warm but no longer "boiling" hot. Puree using an immersion or traditional blender. Taste and adjust seasoning with salt, about 1/2 teaspoon, and freshly ground pepper. Remember, the meat will have plenty of spice rub on them, so don't over-season the sauce.
Add the cocoa powder and mix well to combine. Let sit 5 minutes and stir again to make sure cocoa powder is well distributed. Let cool and pour into a clean glass jar for storing. The sauce can be made in advance and kept for 2 weeks in the refrigerator.