There was a time when the word cocktail meant something other than a 5% rating on Rotten Tomatoes. It implied ingredients. 4 to be exact.
Spirit. Sugar. Water. Bitters.
If and only if a drink had those elements, was it branded with the word cocktail. But—as happens in a culture defined by the fact that everyone is drinking all the time—the rules were eventually relaxed, and soon "cocktail" basically just meant the liquor based thing you were drinking that made you forget both the shame you associate with dancing in public and the rules regulating the naming of things imbibed.
The Old Fashioned, a whiskey cocktail whose very name points to the intended ingredients, also suffered under the governance of a bunch of drunks. Somewhere along the way fruit got shaken into the equation, bubbles added to the water, those horrible cherries (which don't qualify as fruit) muddled the whole thing up, and the soul was stirred right out of the thing.
Which is a shame because the original Old Fashioned is a damn good drink and a perfect example of how a few very minor additions can transform the flavor of a spirit.
Here's how to make one.
The first recorded definition of the word cocktail comes from way back in first decade of the 19th century, a time when I can't imagine the whiskey drank was as good as what we have now. I'm sure someone was making incredible whiskeys then, but I'm also sure that the average whiskey drank needed a bit of help. And that's exactly what an Old Fashioned is. It's a bit of help for your whiskey. The end result should still be a drink that tastes very strongly of whiskey, just with the edges smoothed out a bit. Keeping that in mind, I like to start with a whiskey that has some rough edges. And by rough edges I don't mean a bad whiskey, but rather something hot and spicy that will still have a lot of character even after adulteration. Rye, being by nature a more spicy whiskey, is a great choice here. As is a higher proof bourbon. I recently bough this bottle of Old Weller 107 and it could very well be the best whiskey I've had for that price (keeping in mind that my designating something as "the best whiskey" is generally only done after I've had a bit of said whiskey, and shortly before I decide that I love everyone here and that I'm a really good dancer). Under $30 and you get something that's great on its own but with backbone enough to stand up to cocktails.
Pour 2 ounces of the whiskey of your choice in a glass.
Next up are bitters, which always taste somehow like absolutely none but also every single one of the myriad ingredients used to concoct them. Angostura is a classic well deserving of its ubiquity, and if you only buy one bottle of bitters make it that one. These days I have been enjoying the Fee Brothers apply named Old Fashioned Bitters. A little less sweet than Ango with more of a citrus/cinnamon thing going on, I really love it in simple whiskey drinks like this.
Add 3 dashes of bitters to your whiskey.
As for sugar, it's best to err on having a lighter hand here. You don't want to end up with a sweet drink. The original method was to add a half teaspoon of white sugar to the cocktail glass and dissolve it with a splash of water and some muddling. This is still a great way to make the drink and I have a friend who prefers this method because it leaves the drink more "toothsome." But what I do ninety-nine times out of a hundred is to add 2:1 demerara syrup, which, if you made last week's whiskey sour, you already have in your fridge.
Add a quarter ounce 2:1 simple syrup.
The next ingredient is water. In modern times this comes in the form of ice. Since this drink is served on the rocks and will thus continue to dilute, it's a good idea not to stir in the ice too much. Let it start a bit strong and then change as you go.
Add a few cubes of ice (or one big one) and give it a good stir for about 10 seconds.
Last up is citrus. The original Whiskey Cocktail had a splash of orange liqueur in it, modern terrible variations have a bunch of orange slices shaken into them, while some good modern variations have orange slices that are incorporated with a much defter hand. The constant in all of these is citrus, which does a remarkable job brightening up the whole drink. The common method I prefer is to leave the fruit intact and instead use only the peel, removed with a knife or vegetable peeler. The peel contains aromatic and flavorful oils that are remarkably potent. To get those in your drink simply squeeze the peel over the glass. You'll see the oils spritz out and mottle the top of the drink. Rub the rim of your glass with the outside of the peel and then either plop it in your drink or throw it away. I love seeing how dramatically the zest changes the flavor of a drink. It's a great thing to remember next time you're cooking.
Lemon and whiskey play very well together so don't feel like you only can use orange here. You can also use lemon. You have two options. But you're still just making a drink so try not to get all Robert Frost-y about it, ok.
Add the zest of a lemon or orange.
Drink your cocktail.