Icing Use Note: The pudding icing must be refrigerated for at least 4-hours to allow the spread to thicken. DO NOT spread onto cake prior to recommended chilling time. Sweet Potato: I always have baked sweet potatoes on hand in the fridge because I bulk cook my starches. This allows for this recipe to come together quickly. Oven Method: Bake sweet potatoes in oven on 400F for at least 1 hour or until fork tender. Instant Pot Method: Steam sweet potatoes in Instant Pot for 30 minutes using the “natural release” to release the steam.