- 1 stick (113 grams) unsalted butter
- 1 1/2 cups (300 grams) packed dark brown sugar
- 1 1/2 teaspoons fine sea salt
- 1 cup heavy cream
- 1 teaspoon vanilla
- 2 tablespoons dark liquor, optional
In a large heavy saucepan or skillet over medium heat, melt the butter. Add the sugar, salt, and cream and stir with a rubber spatula until combined. Without stirring, let the mixture cook at a bubbling simmer for three minutes. Be careful not to boil too long, or you’ll end up with chewy butterscotch candies instead of a sauce.
Remove from heat and let cool slightly before stirring in the vanilla extract. Pour into a resalable container, preferably glass. Don’t scrape the sides of the pan into the container or you may end up with gritty pieces of undissolved sugar. You should end up with about 1 1/3 cups sauce.
Serving and Storage: The sauce should be served warm. It can be stored in a jar, in the refrigerator, for up to two weeks. Reheat the butterscotch sauce in a saucepan over low heat.