In a blender, combine the chocolate and 2 cups hot water. Let stand until the chocolate is softened, 1 to 2 minutes. Add the sugar, cinnamon, salt, almond butter and chili powder (if using). Cover the blender and, holding the lid in place, blend on high until smooth, 30 to 60 seconds. Pour in the 1 cup boiling water and stir with a spoon to combine (do not blend). Pour into cups or mugs and serve.