From the book "Peeny Butter Fudge"
Butter the inside of the cake pan, set aside. Combine milk and chocolate squares in the saucepan. Stir over low heat with the wooden spoon until the squares begin to melt or have melted completely. Add sugar and stir. Increase heat to medium and let cook, stirring occassionally, until mixture comes to a low boil. After five minutes of boiling, test the mixture’s readiness by placing a drop of it into a glass of cold water. Keep doing this until a drop forms a tadpole shape as it falls through the water. Turn offf the heat and remove the saucepan from the stove. Add vanilla and stir. Place the saucepan in the large pan or sink of cold water, making sure none of the water enters into the saucepan. Let sit. After a few minutes; lift the saucepan and place palm under it - at first touch the saucepan may be hot,,,,repeat until the bottom of the saucepan is merely warm to the touch. Sitr in the peanut buttter. Beat mixture until it is no longer shiny. Pour quickly into the cake pan. Let cool. Cut the fudge into squares.