Preheat the oven to 350 degrees. Line an 8-inch square baking pan with waxed paper.
Sprinkle nuts in the pan onto the waxed paper. Melt the chocolate pieces; add the powdered sugar and milk and beat well. Spread over the nuts in the pan.
Sift the flour together with the baking powder and salt and set aside.
Cream the sugar and the shortening together; beat in the egg. Add the flour mixture to the creamed mixture alternately with the milk and the vanilla. Pour over the chocolate mixture in the pan. Bake for 45 to 50 minutes. Let stand in the pan 5 minutes and then invert onto a rack. Remove the waxed paper. Cool. Cut into 2-inch squares to serve.
Source: “Homemaker’s Cookbook-Cakes”, The Progressive Farmer, 1971