Preheat oven to 375F and place parchment paper in a 8x8” baking pan. Set aside.
Peel and slice 4 apples very thin (use a mandoline if you have one—just be VERY careful). Add apples to a large bowl and squeeze the juice of 1 orange on top. Stir.
In a medium bowl, whisk together melted butter, sugars, and eggs. Then add in whole milk and vanilla extract, whisk until combined.
Add in remaining dry ingredients and stir until combined.
Pour batter over apples and stir until coated very well. Make sure the apples are separated and all coated well.
This step gets messy, but use your hands to layer and arrange the individual apple slices. Once they all arranged, add the remaining batter on top and press down lightly on the apples. Set aside.
In a small bowl, mix together the guar, cinnamon, and salt for the topping. Sprinkle the sugar mix on top of the apple cake.
Bake the cake for 55-60 minutes.
Once baked, let cool.
While cooling, make the icing if you plan to use it. Cream together the cream cheese and powdered sugar until combined well. Then add in maple syrup while beating on low. Add a pinch of salt and beat again for 1-2 minutes. Drizzle or pipe the icing on top of the cooled cake.