Generously coat the inside of your pot with cooking spray or butter.
Squeeze the lemon juice into a large bowl half full of cool water. Add the apples to the bowl as you work. Strain apples and add to the pot. Add the sugar, cinnamon, nutmeg and apple cider/juice. Give the mixture a stir.
In a large bowl, combine the oats, flour, brown sugar, salt and butter. Stir until crumbly and pour evenly over the apple mixture.
Place the cover on the pot and set timer to 5 minutes on high pressure (pressure cook setting). It will take the IP around 12 minutes to build up pressure before it begins cooking.
When cooking time is done, do a quick release. Remove the cover and let the mixture cool for 10 minutes before serving. Serve straight from the pot or transfer to a baking dish. Serve with a scoop of vanilla ice cream!