Ingredients:

  • 1 cup (2 sticks) Unsalted Butter, cut into 1-inch cubes
  • 1 cup Granulated Sugar
  • 1/2 cup Light Corn Syrup
  • 1 standard can Sweetened Condensed Milk (397g)
  • 1/2 cup, packed Light Brown Sugar
  • 1 teaspoon Pure Vanilla Extract
  • 1/4 teaspoon Fine Sea Salt
  • 1/2 teaspoon Flaky Sea Salt, for sprinkling

Instructions:

  1. Prepare the Pan: Line the 8x8 inch pan with parchment paper, leaving an overhang on two sides. Lightly grease the parchment paper with butter or non-stick spray. Sprinkle the bottom lightly with a tiny pinch of flaky sea salt.
  2. Combine Ingredients: In the deep, microwave-safe bowl (at least 3-quart capacity), combine the granulated sugar, brown sugar, corn syrup, sweetened condensed milk, and cubed butter.
  3. Initial Melt (High Power): Microwave the mixture on 100% power for 2 minutes. Remove, and stir thoroughly until the butter is mostly melted and the sugars are dissolving.
  4. Controlled Boiling (Medium Power): Return the bowl to the microwave. Microwave on 70% power for 2-minute intervals, stirring vigorously after each interval. The mixture will bubble up considerably.
  5. Monitor Temperature: After approximately 4–6 minutes of controlled boiling, begin using the candy thermometer. The goal is to reach 245°F (118°C), the 'Firm Ball' stage. Continue microwaving in short bursts (30 seconds to 1 minute) at 70% power until the mixture hits the target temperature.
  6. Add Finishing Ingredients: Once 245°F (118°C) is achieved, immediately remove the bowl from the microwave. Stir in the vanilla extract and the fine sea salt. Be quick and cautious.
  7. Pour and Set: Immediately pour the hot caramel mixture into the prepared 8x8 inch pan. Do not scrape the sides of the bowl (to prevent crystallization).
  8. Garnish and Chill: Sprinkle the top evenly with the remaining flaky sea salt. Allow the caramel to cool completely at room temperature for 2–3 hours, or chill in the refrigerator for at least 1 hour until firm enough to cut.
  9. Cut and Store: Once firm, lift the caramel slab out using the parchment overhang. Use a sharp, lightly oiled knife to cut into desired squares. Wrap individually in waxed paper or cellophane.