Ingredients:
  • 4 tablespoons unsalted butter
  • 240 ml (1 cup) of tightly packed dark brown sugar
  • 180 ml (¾ cup)  whipping cream
  • 1 tablespoon vanilla extract
  • 1 teaspoon salt
Method:
  1. In a heavy bottomed stainless steel 2 litre (2 quart) saucepan, melt butter over low to medium heat. Just before butter is melted, add all dark brown sugar at once and stir with wooden spoon until sugar is uniformly wet.
  2. Stir infrequently until mixture goes from looking grainy to molten lava. Make sure to get into the corners of your pot, and watch closely to notice how the mixture changes. It will take about 3 to 5 minutes.
  3. Right before you add the cream, the caramelizing brown sugar will begin to look and feel more like liquid and less like thick wet sand.
  4. At this point add all the cream at once and replace your spoon with a whisk. Lower heat a little and whisk cream into mixture. When liquid is uniform, turn heat back to medium and whisk every few minutes for a total of 10 minutes.
  5. After liquid has been boiling on the stove for its 10 minutes, turn heat off and let rest for a minute or two before transferring into a heatproof storage vessel.  Cool to room temperature.
  6. When butterscotch liquid is room temperature, take a small taste. It's important to know what cooked brown sugar and butter tastes like, and what happens when making the  butterscotch flavor.
  7. Whisk in half the salt and vanilla extract. Taste again. Add more salt and vanilla extract until the real taste of butterscotch is achieved.

Chill butterscotch sauce in a non-reactive container with a tightly fitting lid only after sauce has chilled completely. It will keep for one month refrigerated.