Grease and flour a 7” cake pan.
Peel, core and chop apples into small pieces. Toss with cinnamon and 2 tablespoon sugar and set aside.
In a large bowl mix flour, baking powder and salt together and set aside.
In a separate bowl, whisk together oil, orange juice, sugar, vanilla and eggs. Mix wet ingredients into dry ones; scrape down the bowl to ensure all ingredients are incorporated. This batter is thicker than the usual cake batter.
Pour half of batter in the cake pan. Since the batter the thick allow it to spread evenly by gently tapping the cake pan on the sides. Spread half of apples on top of the batter. Slowly pour the remaining batter covering most of the apple pieces. Spread the remaining half apples and any juices on top.
Cover the cake pan with a paper towel and then cover it tightly with aluminum foil. You can skip the aluminum foil by securing paper towel with a rubber band around the pan.
Add 1 cup water to Instant Pot. Place the cake pan on the trivet and carefully place the trivet in the Instant Pot.
Pressure cook for 60 minutes and allow Natural Pressure release.
Carefully take the trivet out and remove the aluminum foil and paper towel. Allow the cake to cool on a wire rack for atleast 5 minutes.
Run a knife on the sides of the cake between the edges and the pan to loosen the cake. Then place the pan on a cup and gently push the sides of the cake pan down for the cake to release on the bottom plate of the push pan.