Bourbon Dark Chocolate Fudge

This is my grandmother's recipe for fudge tweaked by my bourbon-loving self, and it's spoiled me for any other kind.  Fudge-connoisseurs, before you start squawking, I know it's not true fudge (different cooking method), but I defy anyone out there to produce a candy as smooth and dark and delicious as this is.  It's a great example of great ingredients making even simple recipes decadently delicious.

18 oz. good quality dark chocolate (I prefer the Ghirardelli 60% cacao chips)
1 can condensed milk
1 Tbs salt
1 shot bourbon

Melt the chips with the condensed milk and salt in a double boiler over low heat.  Remove the chocolate from the heat.  Stir in the bourbon.  

Press evenly into wax- or parchment-paper-lined 8 inch square pan.  Press a square of parchment paper over the surface of the fudge to keep refrigerator odors out of fudge.  (Chocolate is a scent-sponge.  Trout-scented fudge = not fabulous.)

Turn fudge out onto cutting board and peel off paper. Cut into squares and store loosely covered at
room temperature. 

Makes about 2 pounds.