Mise en place - Break the dried chiles apart and shake out the seeds. Destem and deseed the peppers. Give the chiles, peppers, and prunes a rough chop. Peel and dice the onion. Peel and smash the garlic. Measure out the spices into a small bowl.
Make the broth - Add the dried chiles to a dry pan over medium high heat. Cook, stirring often, until the chiles are charred and fragrant. Remove the toasted chilis from the pan and set aside. Add 1 T oil to the same pan over medium heat. Add the diced onion, the chopped peppers and smashed garlic, and cook until the oniononions soften and become translucent. Stir in 2 t chile powder, 1 t smoked paprika, 2 t cumin powder, 1 T dried oregano, 1 t cinnamon, ¼ t nutmeg and ½ t ground cloves. Pour in the broth, then add the toasted chiles, prunes, and 2 T instant coffee to the pot. Bring to a boil, then turn down to a simmer and cook for about 10 minutes. While the broth is simmering, break the chocolate into small pieces.
Blend and return to the pot - Carefully add broth to your blender jar and blend until very smooth. Return to the pot you used to simmer the broth.
Finish - After blending, stir in 1 t sugar, 1 t salt, ¼ cup tahini, and the chocolate. Continue stirring until the chocolate melts. Adjust seasoning, as necessary.