Ingredients:

  • 1/2 cup unsalted butter
  • 1 cup granulated white sugar
  • 1/2 cup full-fat buttermilk
  • 1 tablespoon light corn syrup
  • 1 teaspoon baking soda
  • 1 tablespoon pure vanilla extract
  • 1 pinch fine sea salt

Instructions:

  1. Combine the 1/2 cup unsalted butter, 1 cup granulated sugar, 1/2 cup buttermilk, 1 tablespoon light corn syrup, and the pinch of salt in your saucepan. Place over medium heat.
  2. Whisk gently as the butter melts to ensure the fat and water based buttermilk don't separate.
  3. Bring the mixture to a simmer. Cook for 7 minutes while whisking occasionally. You are looking for the sugar to be completely dissolved and the mixture to turn a very light amber color. Note: Do not let it reach a hard boil, or the milk solids might curdle.
  4. Remove the pot from the heat completely. Stir in the baking soda. The mixture will immediately begin to foam and triple in volume. Add the 1 tablespoon vanilla extract now. Whisk vigorously for 30 seconds until the foam is uniform and smells like toasted marshmallows.