Popular Kerala sadya dish. Olan is a delicious curry Made with white pumpkin (ash gourd or kumbalanga), cowpeas (red lobia or chawli) and coconut milk. Gluten-free and vegan. Olan is a dish that is part of the Kerala cuisine of the state of Kerala in South India. It is a light and subtle-flavored dish prepared from white gourd or ash-gourd, and black-eyed peas, coconut milk and ginger seasoned with coconut oil. It is usually served as part of a Sadhya.