Cool completely. Store in an airtight plastic container or in a mason jar. This sauce is fantastic with almost any apple dessert or for great sundaes.
You will want to prepare the ingredients and have them at the ready. Timing is very important in any good caramel sauce, so having the butter and cream ready at the crucial point is critical to the success of your sauce.
You will also want to be very careful when preparing caramel sauce; when the sugar syrup hits the right stage to add the butter and cream it will be over 300 degrees F so it is important to take particular care.
It is also very important to use a proper sized pot. Although the recipe only makes about 3 cups, you will need a 2½ to 3 quart/liter heavy bottomed saucepan because the sugar syrup will foam up considerably and produce a considerable amount of steam when the butter is added and again when the cream is added.
These safety tips are not meant to deter, it's just good advice to make these sorts of things when you can take the time without distractions and give it your full attention. A successful caramel sauce is also one that has been given careful attention. With a little practice you will be a caramel ace in no time.
This sauce, minus the rum is my regular recipe for caramel sauce which is also incredibly delicious.
Changing up the spirits in this recipe can make for other delicious sauces. Brandy, cognac or whiskey can also be used. Bourbon as a substitute makes a bourbon caramel sauce that is exceptionally delicious on apple desserts in particular.