Caramel is an amazing thing. It's the Maillard reaction in play, and it turns simple sugar into something complex and delicious. This video from Bon Appetit shows you the secret to making the smoothest, silkiest caramel ever: A dash of cream of tartar.
The recipe itself is simple: A cup of sugar, three tablespoons of water, a half cup of thickened cream, four tablespoons of butter, salt and 1/8th of a teaspoon of cream of tartar. The video shows you the process, but for those who can't watch, start by adding the sugar, water and cream of tartar together, but make sure to prep the other ingredients since you won't want to walk away from your caramel to get everything else once you start cooking.
Then put your sugar/water/cream of tartar mixture on low heat, stirring all the way through and making sure the sugar is all dissolved. Keep the heat low, and once it gets the colour you want and smells nice and toasty, turn the heat down a little bit, and then add the butter, then add the cream slowly. Finish off with a generous teaspoon of kosher salt, and let it cool. Top ice cream with it, use it for popcorn or just about anywhere else you might use a delicious caramel sauce, and you won't regret it. There are a bunch of ingredients, but if you prep them all first, the actual cooking is easy enough, and the results are worth the effort — just don't leave out the cream of tartar.
The Key to The Smoothest Caramel [Bon Appetit (YouTube)]