Preheat an oven to 350 degrees F (175 degrees C). Grease and flour a 10 inch tube pan.
Mix cinnamon, 3/4 cup of sugar, and apples in a bowl; set aside. Combine flour, salt, and baking powder in a bowl. Beat the eggs and 2 cups of sugar with an electric mixer until fluffy. Pour in the flour mixture alternately with the oil. Beat in the orange juice and vanilla until smooth and thoroughly mixed. Pour half of the batter into the prepared pan. Layer half of the apples on top. Pour the remaining batter over, then finish by topping with the rest of the apples.
Bake in the preheated oven until a toothpick inserted into the center comes out clean, about 1 hour and 30 minutes to 1 hour and 45 minutes. Cool in the pans for 10 minutes before removing to cool completely on a wire rack.