First, you’ll need to make a rich demerara syrup because, while you want your chocolate liqueur to be complex, you still want it to taste good. Add the demerara sugar and distilled water to a small saucepan over medium heat and stir. Keep stirring until all of the sugar is dissolved. Let it cool to room temperature before moving on.
Once the syrup is cool, add 1.5 cups of it to your jar. (Cover and refrigerate the remaining syrup to use in cocktails.) Then, add the rum, cacao nibs and cinchona bark to the jar. Before you throw the vanilla bean in the mix, split it and scrape the insides into the jar, then drop in the scraped bean halves. Seal the jar, making sure it’s air-tight, and shake it until all the ingredients are thoroughly mixed. Place the mixture in a cool, dark area to steep, giving the jar a quick shake once a day. Think of it as your daily, 30-second workout.
After 48 hours, remove the vanilla bean halves so the vanilla flavor doesn’t become too overpowering, then continue to steep the mixture for three to four more days—or, if your prefer a seriously intense chocolate flavor, let it sit for a full week. Taste the liqueur every day after the initial 48 hours to monitor its chocolaty levels (it’s the responsible thing to do). We strained ours after it steeped for six days from start to finish, which gave it a deep, chocolaty finish and slight bitter undertone.
When you decide your infusion has achieved the height of chocolate perfection, it’s time to strain all of the solids out of the jar. Get out your sieve or fine mesh strainer and have your funnel, coffee filter and bottle at the ready. Strain the liqueur through the sieve or strainer into a bowl to remove the bulk of the cacao nibs and cinchona bark, pressing the solids to get every last drop of precious liqueur out. Then, place the coffee filter in the funnel and slowly pour all of the liqueur through the funnel into the bottle.