Grease a 8x8 square cake pan with softened butter and line with strips of parchment paper. Grease the parchment paper with butter.

In a small pot, whisk together vanilla extract, cream, butter, and 1 teaspoon of flaky salt. Heat until butter is melted and mixture is warmed.

Clip candy thermometer to side of 3.75 quart pot, whisk together corn syrup and water. Pour sugar into center of corn syrup mixture not letting sugar touch the sides of the pot. Bring pot to a boil without stirring until mixture reaches 300 degrees. Reduce heat to medium-low and stir occasionally until mixture reaches 350 degrees and remove from heat.

Carefully stir in cream mixture. Mixture will bubble. Return pot to stove and heat, stirring constantly, until mixture reaches 248 degrees.

Pour caramel into prepared pan and sprinkle with 1/2 teaspoon of flaky sea salt. Let cool completely then transfer to refrigerator. Chill until caramel is solid and set.

Remove caramel from pan and peel off parchment paper. Using a sharp chef's knife, cut caramels into 1 inch pieces and wrap in waxed paper squares to store. Store on the refrigerator for up to two weeks.