1 cup sugar
1/2 cup whipping cream
1/3 cup water
1/4 teaspoon vanilla
1/2 cup (1 stick) salted butter
1/4 teaspoon flaky sea salt
Put the sugar in the bottom of a large, heavy saucepan over medium-high heat and pour in the water slowly.
Without stirring but watching all the time, heat the pan until the sugar melts and starts to brown.
When it does, swirl the pan very gently to let the mixture brown evenly (if you stir the sugar before it melts, you’ll push sugar crystals up the sides of the pan, and later these may cause the caramel to abruptly crystallize again).
Cook the caramel for five to seven minutes, until it’s a rich, golden brown. Remove it from the heat and add the butter, stirring gently to melt it. Pour in the cream and stir to combine. Last, add the vanilla and salt.
Cool the sauce completely and store it in an airtight jar in the refrigerator for up to 2 weeks. It will firm up somewhat in the fridge, but you can reheat it gently to soften it before serving it again.