This is the fudge by which I measure all others. The recipe was my grandmother's and was passed to my mother. Mom only made this delicious, creamy chocolate confection once a year. A very special treat for a very special holiday... Christmas.
Chop chocolate into small pieces; add chocolate to 2 quart nonreactive saucepan.
To the chocolate in saucepan, add evaporated milk, sugar and corn syrup.
Cook over low heat, stirring until sugar dissolves and chocolate is melted.
Heat to boiling; cover and cook 3 minutes. (Steam in covered pan will help wash down crystals on sides of pan.)
Uncover and cook to softball stage, 235-240ºF (112-116ºC) stirring the mixture frequently. (Soft-ball stage is when a small amount of sugar syrup is dropped into very cold water and it forms a ball that does not hold its shape when pressed with your fingers.)
Remove from heat; add 2 tablespoons butter and allow to cool, undisturbed, to lukewarm. (May place pan in cold water to speed cooling. It is very important to not allow any water to come into contact with the chocolate, and very important not to stir until cooled.)
While mixture cools, lightly grease 8"x8" or 9"x9" pan or baking dish.
Add 1 teaspoon vanilla to mixture when cool.
With sturdy, wooden spoon, beat mixture by hand until thickened, but not too stiff to pour.
Pour into prepared pan/dish and smooth to level.
When firm, loosen from pan and turn out onto wax paper.