Coat the inner pot of a 6-quart Instant Pot with oil. Combine apple and next 6 ingredients (through coconut milk) in inner pot. Close and lock the lid of the Instant Pot. Turn the steam release handle to “Venting” position. Press [SlowCook], and use [Adjust] to select “Less” mode. Press [-] or [+] to choose 6 hours cook time. Stir well before serving. Garnish with toasted cashews and additional diced apple, if desired.