Line an 8x8 inch baking pan with parchment paper and set aside.

In a heavy-bottomed saucepan, combine the granulated sugar, heavy cream, unsalted butter, light corn syrup, and sea salt.

Place the saucepan over medium heat and stir constantly until the sugar has completely dissolved and the butter has melted.

Stop stirring and increase the heat to medium-high, bringing the mixture to a boil.

Continue boiling without stirring until a candy thermometer reaches 238°F (114°C), which is the soft-ball stage.

Immediately remove the saucepan from the heat and allow the mixture to sit undisturbed until it cools to approximately 110°F (43°C).

Add the vanilla extract to the cooled mixture.

Using a wooden spoon or a heavy-duty electric mixer, beat the mixture vigorously until it loses its glossy sheen and becomes thick and opaque.

Quickly transfer the fudge into the prepared baking pan and smooth the top with a spatula.

Allow the fudge to set at room temperature for at least 2 hours before cutting into 1-inch squares.