Drunken Coffee Jello Squares

Adapted from The Food Librarian

1/2 cup cold water
1 3/4 cups strong coffee, hot (I brewed 8 Tbls. French Roast with 2 cups water)
14 oz. sweetened condensed milk (not evaporated milk)
3 packets of Knox unflavored gelatin
3 Tbls. Kahlua or other coffee liquor

8-inch x 8-inch glass baking pan