Full-fat coconut milk eases up the indulgence level of this creamy-cheesy potato casserole.
1 Set rack in bottom third of oven, and preheat oven to 400°F. Coat 13- x 9-inch baking dish with cooking spray.
2 Place onion in small bowl, and strain coconut milk over top. Let stand 10 minutes.
3 Stir together potatoes, coconut milk, Gruyère, and basil mixture in prepared baking dish, and season with salt and pepper, if desired. Evenly arrange potatoes to cover bottom of dish. (Potatoes should be covered with coconut-milk mixture.) Sprinkle Parmesan over top. Bake 35 minutes, or until top is lightly golden brown and potatoes feel tender when pierced with tip of paring knife. Cool 15 minutes before serving.