Prepare your caramel mold: Grease an 8x8 inch baking pan with butter or cooking spray. Line with parchment paper, leaving some overhang on the sides to use as handles later. Grease the parchment paper as well. Set aside.

In a small saucepan, heat the heavy cream and butter over medium heat, stirring frequently, until the butter is melted. Remove from heat, pour into a heatproof measuring cup and set aside

In a medium heavy-bottomed saucepan, combine the sugar and water. Cook over medium-low heat, stirring constantly with a wooden spoon or silicone spatula, until the sugar has dissolved completely. Stop stirring and allow to come to a boil

Continue cooking, without stirring, until the mixture reaches 320°F on a candy thermometer, about 6-8 minutes. It should be a deep amber color

Carefully and slowly pour in the hot cream mixture while whisking constantly. Be very careful as it will bubble up. Continue to cook, stirring frequently, until it reaches 248°F, about 5-10 minutes

Remove from heat and stir in the vanilla and salt until well combined.

Pour the hot caramel into the prepared pan. Allow to cool at room temperature for at least 4 hours or up to overnight.

Once cooled, lift the caramel out of the pan using the parchment paper handles. Peel off the paper and cut into 1-inch squares using a sharp knife coated in butter.

Wrap each caramel individually in squares of parchment paper or cellophane. Store at room temperature in an airtight container for up to 2 weeks.