Directions

1. Preheat oven to 350 degrees F (175 degrees C).
2. Melt together butter and chocolate in a small saucepan over low heat. Remove from heat.
3. Add and stir in brown sugar; cool slightly. Add water, egg yolk and vanilla; beat well. Stir in flour and salt. Set aside.
4. Beat egg whites until stiff peaks form, using an electric mixer at high speed. Fold egg whites into chocolate mixture, then fold in chopped nuts.
5. Pour into greased 9 inch square pan. Bake for 35 minutes or until set around the edges. Cool a few minutes and remove from pan. Cool on rack.