We would make a sauce like this all the time at the bakery I used to work at, but we generally referred to it as cajeta. As far as I'm concerned, why would you ever want to buy store-bought caramel sauce when it's this easy to make at home?
I started with half a cup of sugar and a splash of water, just enough to make the sugar look like wet sand when mixed together with it. I put this over medium-high heat and let it start to melt. After a while, it will start to boil. Keep boiling it until it starts to turn amber. Don't stir it until it gets at least a little color! If you do, it'll all crystalize and you'll have to start over. The amber color will signal to you that the sugar bonds are now too damaged to crystalize. You can start stirring it now, with a wooden spoon, if you like. If one part of the pan starts to color before another, I would even recommend stirring so that that one part doesn't burn.
Now, things are going to happen pretty quick here, especially with only half a cup of sugar. When you start to see little wisps of smoke, remove the pan from the heat and slowly stir in half a cup of cold cream. Be careful! It will steam up right away, so keep your stirring hand (and your pouring hand for that matter) as safe a distance as you can, without stopping them from what they're doing. Now, the cold cream may make the sugar harden. Go ahead and put it back over medium-low heat and stir until the sugar is all melted again, and completely integrated with the cream. Go ahead and let that cool.
Now, I keep a supply of squeeze bottles around from my local restaurant supply store (pictured below). If you don't have a local restaurant supply store, a clean ketchup or mustard bottle is fine. If nothing else, a reclosable plastic container is fine. But what do you do with it? Pour it over ice cream, apple pie, just about anything, really. Resist the temptation to eat it straight. It really is good stuff.