Brown Sugar Pound Cake

Preheat oven to 300 °F. Grease and flour a 10-inch Bundt pan.

Using an electric mixer, cream together 2 sticks butter and shortening and add the dark brown sugar and 1 cup granulated sugar, 1 cup at at time, continuing to beat. Add 5 eggs one at a time, beating well after each addition. Sift flour and baking powder together in another bowl and add alternately with 1 cup milk to creamed mixture, beginning and ending with flour mixture. Add vanilla and mix well. Pour batter into prepared pan. Bake for 2 hours.

To prepare frosting, mix together 1 beaten egg and 1 cup milk and set aside. Place 1/2 cup granulated sugar in a heavy saucepan. Cook over medium-low heat, stirring constantly until melted and brown. Add water and stir until sugar is dissolved. Add remaining 2 1/2 cups granulated sugar. Mix egg with milk and stir into sugar mixture. Add 1 stick butter, vinegar, and salt. Cook to softball stage (236 °F on a candy thermometer), stirring constantly. (A small amount dropped in a glass of water will form a soft ball. If you remove it from the water it will flatten out). Cool to lukewarm. Beat until creamy and spread on cake.