DIRECTIONS

In a large mixing bowl, cream butter and sugar until light and fluffy. Add eggs and vanilla; mix well. Combine the flour, cocoa and cream of tartar; gradually add to creamed mixture. Stir in nuts. Spread half into a greased 13-in. x 9-in. baking pan.
    For filling, combine the coconut, condensed milk and vanilla; carefully spread over batter in pan. Top with the remaining batter. Bake at 350° for 40-45 minutes or until a toothpick inserted near the center comes out clean. Cool on a wire rack.
    For frosting, combine the sugar, milk and butter in a saucepan; cook and stir until sugar is dissolved. Add the marshmallows and chocolate chips; cook and stir until melted. Remove from the heat; stir in vanilla. Cool until frosting reaches spreading consistency, about 25 minutes. Spread over the cooled brownies. Cut into bars. Yield: 4 dozen.