To make this sauce dairy-free, use ghee rather than butter. If your butter or ghee breaks, it’s because the temperature changed too rapidly. Try to keep the boiling temperature at around 212°F (100°C), but not over 240°F (116°C), or the soft ball stage on a candy thermometer. It’s important that your ingredients come to temperature together. Stirring in only one direction will also help keep the butter from separating. You can save a separated caramel by whisking vigorously and then transferring it to a bowl. Place the bowl in the freezer and whisk every 10 minutes or so until the caramel comes together and firms up. As it gets colder, the butter will harden and become easier to mix in.
Are you in a hurry for thick caramel? Transfer the finished caramel to a small metal mixing bowl, throw it in the freezer, and stir occasionally until completely cool and thick, about 20 minutes. Variation: Browned Butter Salted Caramel Sauce. Before beginning the recipe, brown the butter following the method on page 360. Use a rubber spatula to transfer the browned butter to a medium-sized mixing bowl, scraping up the browned bits as well. Place the bowl in the freezer to harden for 15 to 20 minutes, then proceed with the recipe as written.