Combine bourbon, NOLA, and bitters in a mixing glass. Add ice and stir to chill, then strain into a rocks glass over ice. Garnish with a twist if you like, or a coffee bean. Bonus points for melting a spot in the top of your ice cube to hold the bean. To make syrup: In a small saucepan, combine equal parts water and brown sugar. Warm on low heat and gently stir until the sugar is dissolved. When syrup has cooled: Combine bourbon, coffee liqueur, syrup, and chocolate bitters in a mixing glass. Add ice and stir to chill, then strain into a rocks glass over ice.