Place a heavy-bottomed saucepot over low–medium heat. Add the sugar and begin stirring constantly to prevent burning.

Continue stirring as the sugar melts; once it is fully melted and reaches a light butterscotch color, remove the pot from the heat.

Carefully add the butter (warm if possible) and whisk vigorously until fully incorporated.

Slowly pour in the room-temperature whipping cream while whisking continuously until smooth and combined.

Stir in the vanilla and salt, taste and adjust salt if needed. Allow to cool slightly before using; store in a jar in the fridge.