This caramel sauce would be delicious drizzled over a light frosting. It also accompanies the walnut topping posted here.
You can double the recipe if you wish; the caramel sauce will keep, covered, in the refrigerator for up to a month. It’s a good idea to make the caramel early in the day or even a day or more ahead, because it must be cooled to use with the whipped cream.
If you don’t have time to make it ahead, you can cool it fairly quickly by placing the glass measure in a bowl filled with ice water, making sure the water doesn’t get into the measure.
Stir frequently, and remove the measure from the ice water when the caramel sauce is thick. If you have refrigerated it, you will need to let it come to room temperature before it will be of a pourable consistency.
1/2 cup granulated sugar
2 tablespoon cold water
1/2 cup heavy cream
1 tablespoon unsalted butter
1/4 teaspoon pure vanilla extract
Put the sugar and water in a 2-cup liquid measure that is microwave proof (such as a glass Pyrex measure). Cover the measure snugly with plastic wrap and microwave it for about 3-5 minutes, or until it starts to turn golden.
The amount of time varies according to the wattage of your microwave oven. WATCH CAREFULLY, and check every 30 seconds after you have reached the 3-minute mark, because the sugar will turn from golden to burnt very quickly.
Remove it from the oven using an oven mitt, and uncover it very carefully to avoid burning yourself with steam. It helps to use a fork to pull the plastic wrap away from the glass measure, so your hand is not too close to the steam.
Drizzle in the cream slowly. The sugar syrup will bubble up when you do this, and may become hard, but don’t worry – it will melt again when you return it to the microwave. Add the butter. Place it in the microwave, uncovered, for 1 minute.
Remove and stir to be sure any sugar syrup that hardened is dissolving. Return the measure to the microwave and microwave again for 30 seconds, until it is a rich dark brown.
If it is not a rich brown, return the syrup to the microwave and repeat in 20 second intervals until the caramel sauce is a deep, rich, caramel brown. Set it aside to cool.