Beat the eggs with the sugar.

Melt the butter into top of a double boiler and stir in the chocolate when the butter has melted. Be sure the water in the double boiler is hot but not boiling, and that the bottom of the pan with the butter and chocolate does not touch the water.

When the chocolate has melted, stir it into the egg/sugar mixture, beating it well. Stir in the vanilla

Sift the 1/2 cup flour with the baking powder and salt and stir them into the chocolate mixture.

Dust the walnuts with a teaspoon of flour, and add them to the batter, stirring until the mixture is smooth.

Bake in a buttered 9-inch pan for 30 to 40 minutes in a 350 degree oven.
40 Minutes