Grease and flour tube pan. Peel and slice 6 apples (thin slices). Mix cinnamon and 5 tablespoons sugar and sprinkle over apples. Mix flour, 2 1/4 cups sugar, oil, eggs and salt. To this add orange juice, vanilla, and baking powder. Layer bottom of pan with 1/3 apple slices (don't let apple slices touch side of pan). Pour 1/2 of batter over apples. Spread 1/3 apples over batter and pour the remainder of batter over apples. Layer top of batter with the remaining 1/3 apples. Bake at 350ºF. for 1 hour and at 300ºF. for 45 minutes. Total baking time 1 3/4 hours.