Nanny Hartenbaum's Chocolate Cake

Preparation

1. For cake:

   Step 1

   Preheat oven to 350°F. Lightly grease 13 x 9 x 2-inch baking pan. Combine 1 cup water and chocolate in heavy small saucepan over low heat. Stir until chocolate melts and mixture is smooth. Let cool 10 minutes.

   Step 2

   Using electric mixer, beat 1 cup butter and dark brown sugar in large bowl until fluffy, about 3 minutes.

   Step 3

   Add eggs 1 at a time, beating well after each addition (mixture will resemble thick frosting). Stir baking soda into chocolate mixture. Mix flour into butter mixture alternately with chocolate mixture in 2 additions each.

   Step 4

   Pour batter into prepared pan. Bake until tester inserted into center of cake comes out clean, about 40 minutes. Transfer to rack and cool completely.

2. For frosting:

   Step 5

   Stir chocolate and butter in heavy small saucepan over low heat until melted and smooth. Remove from heat. Sift powdered sugar into medium bowl. Add chocolate mixture, 1 tablespoon water and vanilla and stir until smooth. Thin to spreading consistency with more water if necessary.

   Step 6

   Spread frosting over cake. (Can be prepared 1 day ahead. Cover with foil and let stand at room temperature.) Cut into squares and serve.