In a medium saucepan, combine 2 cups of granulated sugar and ½ cup of unsweetened cocoa powder. Slowly pour in 1 cup of whole milk, stirring continuously until the mixture is smooth and uniform, free of lumps.

Place the saucepan on the stove over medium heat, stirring constantly to prevent sticking. Bring the mixture to a gentle boil.

Stop stirring and allow the mixture to boil uncontested for 5 minutes.

Immediately remove the saucepan from the heat. Stir in ½ cup of unsalted butter and 1 teaspoon of vanilla extract, mixing vigorously.

Let the fudge mixture cool down for about 5 minutes, stirring occasionally. If adding chopped nuts, fold them in now.

Prepare a 9x9 inch baking pan by greasing it or lining it with parchment paper. Pour the fudge mixture into the pan.

Leave the fudge at room temperature to cool completely for 1-2 hours.

Once cooled, turn the fudge out onto a cutting board and slice into squares.