Will Cinnamon ever dissolve in a cocktail?

Cinnamon is the bark of a tree. It is either sold as rolled strips of bark (=cinnamon sticks) or ground.

It will not dissolve, neither in water nor in alcohol.

What you want to do is basically the same as was done commercially with the vanilla extract you are already using:
Extract the taste, then discard the bark itself.

• Alcohol is a good choice for extracting volatile aromatics. You could try and soak a few cinnamon sticks or a few tablespoons of ground cinnamon in a "neutral" alcohol like vodka or - if you are using it exclusively for your signature drink - use the brandy. This process might take from a few days to a few weeks, so nothing you can do "on the spur of the moment".

• Another good carrier for the cinnamon taste would be water. You can simmer a few cinnamon sticks in water, then sieve. This is the same method that is used for mulled wine or mulled cider. To extend the shelf life of the "cinnamon water", you might considering turning it into simple syrup by boiling it with an equal amount of sugar.

Whether you use water or alcohol is a question of personal taste and planned other uses. The shelf life of an alcohol based extract might be longer, but with a sufficiently high sugar content, clean handling and refrigeration the syrup will last long, too. Time is a factor: The syrup can be ready and cooled in an hour or so, whereas the alcohol will take significantly more time.

Both methods work for vanilla, too - you could even make a "instant mix" for your drink.

Be warned, though: Filtering ground cinnamon from a liquid can be quite a hassle. It tends to clog coffe filters, but is too fine to be held back by a sieve. If you decide to use ground cinnamon because that's what you have at hand, consider letting it settle at the bottom of your container and carefully decanting the liquid from top. A coffe filter or a cloth-lined sieve can catch stray particles. You should get much better results by using whole or coarsely crushed cinnamon sticks.

There has been an ongoing discussion on what kind of cinnamon to use, so a short wrap-up here:

Cinnamon is derived from a group of plants, which vary in their properties and compounds. Especially coumarin, a substance also found in tonka bean, woodruff and other plants, has been widely discussed for its toxicity and is regulated in the EU.

• Cassia cinnamon has the highest content whereas
• true / Ceylon / Sri Lanka cinnamon contains only traces.

From a culinary point, the cheaper cassia, which contains more bark and is usually sold ground or in pieces, is often considered inferior in taste to the true cinnamon, which often comes in sticks.

I will not venture a statement here, neither on health nor culinary claims.
I am sure every reader of this post is capable of making an informed decision.

I don't think it will ever dissolve in an edible solution. However it will readily infuse to both water and alcohol. So instead of trying to retain the cinnamon itself in the solution, just infuse it. Once the flavor has made it's way into the alcohol or water then sieve through a fine mesh. You'd be better off doing this with cinnamon sticks as they are easier to strain :)

I actually dealt with a very similar problem when I decided it would be nice to have coffee with a cinnamon taste - and of course it is! But I didn't want to buy a flavor syrup, and I had a ton of ground cinnamon available.

I eventually settled on adding even just a little bit (less than a teaspoon) of ground cinnamon to the bottom of a coffee filter before adding coffee (if you add it after the grounds it will make a mess of your coffee maker!). The result: the whole pot of coffee had an obvious and pleasant cinnamon taste, even from that little bit of powder! Yet in the pot and in my cup, there was little to no sign of the ground cinnamon.

So to make your very own "extract" is actually quite easy, and indeed you can make it quickly instead of slow infusing (like sun tea) by the same method as regular tea: use heat!

Add the desired amount of alcohol to a suitable small container (start small for testing), like a clean sauce pan, along with a few teaspoons of cinnamon and heat the alcohol. You don't want to take it to the boiling point of either water or the lower boiling point of alcohol - so just use a low heat until it's nice and warm. Within 5 minutes of such a treatment you'll have lots of flavor. Don't be afraid of the heat though - even if alcohol is briefly boiled you might still expect up to 85% of the original alcohol to remain! It just might be of a slightly lower proof, and of course there's a risk of introducing some odd flavor from the pan.

If you have the time, take it off the heat and just let it sit until cool for an even stronger flavor. Regardless, when you are ready pour your tasty extract through a coffee filter and - voila!

If the flavor is too strong, you can mix it with more unflavored alcohol to dilute the effect. If too weak, add more cinnamon and/or let it spend more time in the heat.

You can do it with pretty much any alcoholic beverage, and this process is pretty much the same as with making a hot spiced wine like Glühwein - with the coffee filter as just a handy way to allow you to use powdered cinnamon and end up with a smooth beverage clear of floaty bits.

No, ground cinnamon won't dissolve in a cocktail like that. I'd use a bit of syrup, extract or cinnamon liqueur instead, perhaps Goldschläger, and plop in a (reusable) cinnamon stick as a garnish.

I have a simple answer that I think is ideal. Go to a store such as Whole Food's Whole Body or use Amazon and look for the herbal extract section. I happen to use a cinnamon extract from Herb Pharm that costs around $12 (on Amazon - Whole Body is a bit more). As you can imagine, this is a pure, organic extract of some of the best real cinnamon available. (Read about real and 'sorta' cinnamon on Wikipedia.) While it's only sold in small 1 fl. oz glass bottles that includes a dropper, each bottle lasts me 6 months or so. You have never enjoyed cinnamon flavor if you haven't used something like this. I put a drop or so into yogurt, or in salad dressing (not enough to taste it but it makes a real difference), sauces...the list goes on if you are a cinnamon lover. Nothing else compares.

As already mentioned, cinnamon is not going to dissolve. As you require both cinnamon and vanilla flavouring in what appears to be quite a lot of sugar, I would suggest making a cinnamon and vanilla sugar. Simply stick a vanilla pod and several cinnamon sticks into a screw-topped jar full of sugar. "Bruise" both the pod and the sticks well before immersing in the sugar. Give the jar a good shake every now and then. It will take a few days for the sugar to take up the aroma, but it will permeate the contents of the jar, getting stronger over time. Use the sugar as needed and top up with sugar and shake each time the level goes down below a 1/2 to 3/4. Alternative would be the same method but omitting the vanilla pod/s and using either homemade or commercial vanilla sugar instead.

Alternately make your own flavoured cinnamon syrup by boiling sugar with water and a couple of sticks of bruised cinnamon. Pour into a scalded screw-topped bottle and store in a cool dark place. It will keep indefinitely.

Cinnamon Extract (McCormick makes one) or cinnamon essential oil would be your best bet, in my opinion. Cinnamon essential oil is going to be much stronger and, if you choose to use an essential oil, you need to be VERY CAUTIOUS. The essential oil industry is barely regulated and, from what I've read, a product only has to contain 5% essential oil to be marketed as "100% pure." The remaining 95% can be comprised of products that should not be ingested. I, myself, use a cinnamon bark essential oil for some things but it has been tested and approved by the FDA as GRAS (generally regarded as safe for internal consumption).