Combine marshmallows, morsels, and unsweetened chocolate in large bowl.
Combine sugar, evaporated milk and butter in med sized heavy sauce pan.
Bring to a boil over med heat, stirring frequently;
boil for 6 minutes, stirring constantly.
Pour over marshmallow mixture;
stirring until all is melted and smooth.
Add nuts and liqueur.
Pour into buttered 8-inch square baking pan; cool.
Chill until firm, cut into bite sized pieces.
Makes about 3 dozen pieces.
I like bigger pieces so maybe 1 1/2 dozen is a little more realistic....<[:-}