Directions

1. Preheat oven to 350 degrees F (175 degrees C). Grease a 9x13 inch pan. In a heavy saucepan combine the 1/3 cup of flour and water. Cook over medium heat stirring constantly until thick. Transfer to a mixing bowl and set aside to cool.
2. In a small saucepan, melt butter. When butter has melted, add the cocoa and mix until smooth; set aside to cool. Beat the sugar and vanilla into the cooled flour mixture. Stir in the cocoa mixture until well blended. Combine the flour, baking powder and salt, stir into the batter until just blended. Fold in walnuts if desired. Spread evenly in the prepared pan.
3. Bake for 20 to 25 minutes in the preheated oven, until a toothpick inserted into the center comes out clean. Cool before cutting into bars.