Impossible Hot Fudge Pudding Cake

1 cup Bisquick baking mix
1 cup sugar
3 tablespoons unsweetened cocoa powder
1/3 cup unsweetened cocoa powder
1/2 cup milk
1 teaspoon vanilla extract
1 2/3 cups hot water

Heat oven to 350 degrees F. Grease an 8-inch square pan.

Mix Bisquick, 1/2 cup sugar and 3 tablespoons cocoa powder. Stir in milk and vanilla extract until blended. Sprinkle evenly with remaining sugar and cocoa powder. Pour water over top. DO NOT STIR. Bake 40 minutes or until top is firm. Dust lightly with confectioners' sugar if desired. Spoon into dessert bowls while hot. Tastes great with a scoop of vanilla ice cream or whipped topping on top.