It’s funny how a long journey can bring  you back to the place where you started. 

Today we’re revisiting one of the  earliest cocktails we made on this  

channel, the Rum Old Fashioned. And we’re making it even butter. 

I mean better. Well, both really. 

This is the Chocolate Rum Old Fashioned 2.0. And it really was a journey to get to the  

recipe I’m happy with. You’ll see why later. 

It’s got all of the best parts of a chocolate  chip cookie combined with a Rum Old Fashioned. 

And for garnish, a chocolate chip cookie based  on a recipe from Jeffrey Morgenthaler himself. 

We’ll really cover all of the cravings.

Welcome to the fourth and final episode  of our Rum & Chocolate Masterclass. 

In the true Artisans of Taste spirit, which is a  programme championed by Diplomatico Rum, I went  

on a mission to elevate the simple but delicious  Rum Old Fashioned which we covered back in 2020. 

That was a pretty straightforward Old Fashioned,  made with Diplomatico Reserva Exclusiva rum,  

rich demerara syrup, homemade chocolate and  coffee bitters, stirred with the addition of  

an orange peel, served in a rocks glass over a  clear ice block, and garnished with a piece of  

dark chocolate sprinkled with salt. Small additions to the classic that  

made it its own, but also something we  can now build upon and develop further.

And that exploration, or the journey to try  and come up with something new, is often what  

makes mixology so fun, but also challenging. The final recipe ended up being pretty simple,  

but it really took me a lot of  trial and error to get it right. 

You don’t usually get to see the R&D part of  the process, but I think it’s important for  

everybody to know that new cocktail ideas don’t  always pop into your mind as a finished recipe.

My first draft was a cookie syrup made  with two enzymes, amylase and glucosidase. 

In short, amylase breaks starches  into dextrins and sugars,  

and glucosidase takes those dextrins down  to glucose for sweetness and fermentability. 

The syrup tasted great, but with the small  amount, it wasn’t pungent enough to turn the  

Old Fashioned into a true cookie experience. If you have any ideas on what cocktails  

a cookie syrup might be great  in, drop those in the comments.

The second attempt was a cookie  milk wash, like we did with the  

Donut Old Fashioned and Brownie Manhattan. That was of course inspired by James Hoffmann’s  

“Drinking Donuts in Coffee” episode. The method worked great in the Donut  

Old Fashioned, but even then we ran into a  scenario I really wanted to avoid with this one. 

Alongside a slight starchy note, the cocktail  also turned cloudy when chilled with ice. 

This phenomenon, known as louching,  or the Ouzo effect, happens when oils  

which are soluble in alcohol at higher  concentrations separate out when diluted. 

Long story short, I wanted the cocktail  to look just as good as it should taste.

So it was back to the drawing board, and  then I realized I have to look at the  

cookie as the sum of its parts and start there. Splitting the cookie into components meant I can  

incorporate them separately into the drink. Chocolate, butter, sweetness, vanilla,  

nuttiness, salt… it all came together after that. So here are the ingredients that will make our  

improved Chocolate Cookie Rum Old Fashioned. First, the brown buttered rum,  

adding body and rich buttery, nutty notes. Next, the cacao liqueur, giving us notes  

of chocolate and vanilla, plus the sweetness. Instead of the regal stir with the orange peel,  

I’ll be adding orange bitters,  skipping the coffee in this recipe. 

If you’d like those notes in the  cocktail as well, feel free to  

add a few beans for a caffeinated regal stir. And the salt we added on top of the chocolate bar  

is of course being added as saline solution. To really bring home the point of what the  

whole cocktail tastes like, we’ll add the  garnish of a whole chocolate chip cookie.

So, now that we know what ingredients  did end up coming together nicely,  

let’s go over how to make those ingredients. We’ll be using the sous-vide technique for both,  

because that gives us the most  control over temperature and time,  

while also ensuring a very precise  and efficient infusion of flavors.

For the first part of making the cacao  liqueur we’ll need crushed cacao nibs,  

cacao butter, vanilla bean, and  Diplomatico’s Mantuano rum as the base. 

Sugar and dilution come last. Mantuano is Diplomatico’s versatile,  

medium-bodied blend, aged for up to  8 years, with notes of dried fruit,  

vanilla, and a gentle spice. It’s perfect for infusions like  

this because it gives us a rich backbone  while still letting the chocolate shine. 

We already covered how to make DIY white crème de  cacao, but the dark version is known for a richer,  

more intense chocolate flavor and a deep brown  color, so it will be perfect for our cocktail.

Into a sous-vide bag, add 14 oz or 420 ml of  Mantuano rum, 40 grams of crushed cacao nibs,  

125 grams of cacao butter, and 2 grams  of scraped-out and chopped vanilla bean. 

Seal the bag under vacuum so  nothing escapes during the infusion. 

Place it into a sous-vide bath set to 55  °C or 130 °F

and let it infuse for 4 hours, shaking the bag occasionally  to keep everything well mixed.

As that starts cooking, we’ll make  our brown buttered rum, and to really  

infuse those buttery flavors into the rum,  we’ll add it into the same sous-vide bath. 

And as the name suggests,  you’ll need just butter and rum. 

Just like 5 years ago, we’re again going  with Diplomatico’s Reserva Exclusiva. 

It’s smooth and luxurious, which makes it  an incredible base for a Rum Old Fashioned. 

Here we’ll make it even more decadent  by washing it with browned butter first.

Add 40 grams of unsalted butter to a  small pan and gently heat until melted. 

Keep stirring with a spoon  so the solids don’t burn. 

The butter will foam, the water will evaporate,  

and you’ll start seeing  golden specks at the bottom. 

That’s where the nutty, toasty flavor comes  from, so we’re not straining that out. 

When the butter fully turns a deep golden  brown and smells wonderfully nutty,  

carefully pour it into a jar and top it  up with 400 ml of Reserva Exclusiva rum. 

Keep in mind that the butter will still  be hot, so carefully stir to combine. 

Seal the jar and place it into the  sous-vide bath alongside our cacao infusion,  

cooking for the same 4 hours, shaking it  occasionally to help the flavors mingle.

Once the time is up, chill both infusions to  room temperature, then place them in the freezer. 

You’ll see the butter solidify in the jar,  and the same for the cacao butter in the bag,  

making it easy to remove only the liquid from  both, but the infused buttery and nutty notes  

will be in there as well. For the brown buttered rum,  

we simply filter it through a coffee filter,  wait until it’s done and we have a clear result. 

Then we bottle, add a label, and that’s it. We strain the chocolate liqueur the same way,  

and don’t be afraid to re-use the  butter, it still has plenty of flavor. 

We use a combination of both for the chocolate  chip cookies that will make the garnish.

Once that’s strained as well, we need  to measure how much we ended up with. 

To get the sweetness and dilution just right, we  need to add 40 grams of brown sugar and 30 grams  

of water for every 100 ml of the infusion. Once I have the right amounts measured,  

I’ll add one more step, which is optional, but  it will give the Old Fashioned extra body and  

a silky texture: gum arabic. Add 1.5 grams of gum arabic  

for every 10 grams of water. Use hot water and a magnetic stirrer  

for a quick result, or let it hydrate overnight. Once that’s mixed, we can add in the sugar,  

and finally the cacao- and vanilla-infused rum. Once the magnetic stirrer does its job, you’ll  

end up with a wonderful mixture that is probably  not sweet enough to be called dark crème de cacao,  

but trust me, flavor-wise it’s just as  good as anything you can get in the shop.

Bottle the liqueur, add a label, and, if  you like, filter it again after a couple  

of days for even more clarity. It has an intense chocolate aroma  

with hints of vanilla and gentle  nuttiness from the cacao butter. 

It’s smooth, round, and coats  the mouth with lingering cacao  

notes that pair perfectly with the  brown-buttered rum we made earlier.

We have the ingredients for the cocktail,  

let’s just quickly run through how to make  Jeffrey Morgenthaler’s chocolate chip cookies. 

Even if you’re not into cocktails and you  somehow made it this far into the episode,  

you’ll want to save this link, because  these cookies are the real deal.

You’ll need the classics: butter, white and  brown sugar, eggs, vanilla, flour, baking soda,  

salt, and of course, plenty of chocolate chips. Cream the butter and sugars, whisk in the eggs  

and vanilla, then fold in the dry ingredients. Add the chocolate chips, scoop onto a baking tray,  

and bake at 400 °F or 205 °C for 10 minutes, or  until golden brown with a slightly soft center. 

Very important last step: sprinkle some  flaky sea salt once you take them out. 

The recipe is on Jeffrey’s website  — I’ll link it in the description,  

so you can try it for yourself.

Now all we have to do is  assemble this wonderful cocktail,  

and then it’s the best part: enjoying it. Get your well-chilled mixing glass first,  

and the clear ice block is already tempering  in the rocks glass, waiting for the cocktail. 

First I’m going in with 1½ oz or 45 ml  of our brown buttered rum, followed by ½  

oz or 15 ml of our chocolate liqueur. Next, 3 dashes of orange bitters. 

And lastly, to boost all of the  flavors, 6 drops of 20% saline solution. 

Now add plenty of ice and stir  until perfectly chilled and diluted. 

Then strain the cocktail over  the large clear ice cube. 

Garnish with a chocolate chip cookie on the  rim, and if you want to take it even further,  

add a small spoonful of orange marmalade on top  of the cookie for a sweet-and-citrusy bonus bite.

The aroma hits you first: rich  cacao, butter, and a hint of orange. 

The first sip is decadent: smooth dark  chocolate up front, balanced by the warmth  

of the rum and a bright lift from the bitters. It’s well-rounded, with a silky mouthfeel  

that makes you want to take sip after sip,  especially when you enjoy it with the cookie. 

Delicious.

And with that, we wrap up our  4-part Diplomatico cocktail series. 

Learn more about Artisans of Taste  through the link in the description. 

We’ve gone from tiki riffs, improved  classics, to hot-and-cold creations,  

and now, a dessert-style Old Fashioned. If you have a favorite way of adding chocolate  

to your cocktails, let us know in the comments. Or keep it to yourself so you can apply to this  

year’s Artisans of Taste and it  just might take you to Brazil. 

If you missed any of the episodes  along the way, here’s the playlist. 

I’ll see you next time, but for now, I’ve  got a cookie and an Old Fashioned to enjoy. 

Cheers.