In a medium-sized mixing bowl, whisk together the brown sugar, flour, cocoa powder, eggs, cinnamon, corn syrup, vanilla, bourbon, salt and the melted chocolate mixture. Mix until thoroughly combined and smooth.
¾ cup packed brown sugar, 3 tablespoons all-purpose flour, 1 tablespoon unsweetened cocoa powder, 3 large eggs, 1 teaspoon ground cinnamon, ¾ cup light corn syrup, 1 teaspoon vanilla extract, 2 tablespoons bourbon, ¼ teaspoon fine sea salt