Brown Derby Black Bottom Pie recipe:
1 envelope (or 1 tablespoon) unflavored gelatine
3/4 cup sugar
1/8 t-spoon salt
1 egg yolk, slightly beaten
3/4 cup milk
4 squares unsweetened chocolate
1 cup icy cold evaporate milk, whipped
1 t-spoon vanilla
1 9-inch backed pie shell
1 cup heavy cream, whipped and sweetened
Directions: Mix gelatine, sugar and salt in top of double boiler. Combine egg yolk and milk and add to gelatine mixture. Add 3 squares of the chocolate. Cook over boiling water until chocolate is melted, stirring often. Remove from heat and beat with rotary beater until smooth. Chill until thickened. Fold in whipped evaporated milk and vanilla. Turn into shell and chill until firm. Spread with whipped cream. Shave remaining 1 square chocolate into curls with vegetable slicer; place “lattice” fashion on top of pie.
Source: “Brown Derby Restaurant Shares Famous Black Botton Pie Recipe,” Rockford Crusader, November 13, 1953.