Method
Mix all dry ingredients together using a mixer on slow speed until thoroughly combined
Add combined wet ingredients and mix on slow until just combined. Scrape down the side of the bowl to ensure even mixing
Next cut a circle of baking paper and put it on the bottom of your cake tin. (make sure your tin will fit inside the Instant pot bowl)
Grease the paper on the bottom and the sides of the tin with butter or oil release spray. (We actually lined the sides of our tray with baking paper also)
Put in the wet mix to the cake tin to ¾ full no more.
Wrap the whole cake tin in Aluminum foil quite tightly.
Put 2 cups of water into the Instant Pot bowl and put in the trivet.
Lower the wrapped cake tin in using two slings (folded up foil to about 1 inch wide) made of Aluminum foil. When the cake is in fold the slings down a little so you can put the Instant pot lid on.
Set to pressure cook - High for 75 minutes. Use the fast release button to let out the pressure when the timer is finished
Open the foil off the top of the cake - check it is cooked, by putting a thin skewer in the cake, and if it comes out clean the cake is done. If the cake is not ready put in again for another 15 minutes.
Making the Frosting. Sieve the Icing sugar to remove all lumps.
Combine the cream cheese, icing sugar, lemon juice, and vanilla using a mixer. Mix on 1 or slow speed to combine. Then beat on 3 until smooth and creamy. Top the cake using a frosting spatula