Instructions:

1. Grease a square pan with butter. You can also opt to line it with waxed paper instead.
2. In a sauce pan, mix the chocolate, sugar, half-and-half, corn syrup and salt. Stir gently over medium low heat with a wooden spoon until the mixture begins to boil. Stop stirring once the mixture boils.
3. Clip the candy thermometer to the side of the sauce pan. Don’t let it touch the bottom.
4. Continue cooking the syrup until it reaches about 235° F–240° F. While it cooks, dissolve any sugar crystals clinging to the sides of the pan using a pastry brush dipped in warm water.
5. Remove from heat and rest until it cools down to 110° F.
6. Add vanilla and butter and stir with a wooden spoon. Keep stirring until the fudge sets up and stiffens. Do this for around 15 to 20 minutes.
7. Pour the mixture on the greased pan.
8. Press it down with a greased spatula or by hand.
9. When cooled to room temperature, remove from pan and cut into squares.