Over Seas Fudge (Grandmother Brown's [Goff's] recipe)

1 lb.  confectioners' sugar
3 Tb  top milk (heavy cream)
3 sq.  bitter sweet chocolate
1       egg, well beaten
1 Tb  butter
1 tsp  vanilla
pinch of salt

Melt chocolate and butter in top of double boiler. Add beaten egg, milk, salt and vanilla. Gradually add sifted confectioners' sugar, beating well between additions. If necessary, add 1 more tablespoon (max) of top milk. It will be quite stiff. Spread in an 8 X 8 buttered pan.