Mrs. D's Chocolate Peanut Fudge

1 1/2 cups unsalted shelled peanuts
3 tablespoons plus 1/2 teaspoon unsalted butter
2 cups granulated sugar
1 cup whole milk
1/2 cup Hershey's unsweetened cocoa
pinch of salt
1 teaspoon pure vanilla extract
measuring cup, measuring spoons, baking sheet with sides,
9- by 9- by 2-inch square cake pan, 2 1/2-quart saucepan, whisk, candy/
deep frying thermometer, rubber spatula.
Preheat the oven to 325 degrees Fahrenheit

Toast the peanuts on a baking sheet in the preheated oven until golden brown,
about 6 to 7 minutes. Remove the peanuts from the oven and set aside until
needed.

Lightly coat the insides of a a 9- by 9- by 2-inch square cake pan with 1/2
teaspoon butter.

Heat the sugar, milk, cocoa, and salt in a 2 1/2-quart saucepan over medium
heat. Stir until the mixture is smooth and the sugar is dissolved. Bring to a
boil, then adjust heat to medium-low and allow the mixture to cook until it
reaches a temperature of 245 degrees Fahrenheit, about 22 to 25 minutes. Use
a rubber spatula to scrape down the sides of the saucepan every 5 to 6 minutes.
Remove the pan from the heat. Vigorously stir in the remaining butter and
vanilla. Fold in the peanuts and pour into the prepared cake pan. Allow to
cool to room temperature, about 45 minutes. Cut into desired size and serve.