Heat 1 cup of the brown sugar, ½ cup of the milk, and the chocolate in a double boiler until the chocolate melts. Cool. Beat shortening to soften; gradually add the remaining 1 cup of brown sugar and cream until light and fluffy. Add vanilla and eggs; beat until mixed. Sift the flour, baking soda and salt together; add to the creamed mixture alternately the remaining ½ cup of milk. Beat smooth after each addition. Add the chocolate mixture and beat well. Put the batter into 2 prepared 9” round cake pans and bake at 350F for 30 minutes. Fill and frost with frosting of choice.