In saucepan of boiling water, cook carrots until very tender, approximately 25 to 30 minutes.

Reserving 1/2 cup of the cooking liquid, drain cooked carrots and transfer to blender. Add cashew butter and purée mixture until smooth. If purée appears too thick, add some of the reserved cooking liquid slowly until you achieve desired consistency. Season, to taste. Cover and keep warm.

Pat scallops dry with paper towels, ensuring they are fully dried to prevent them from steaming during the cooking process. Season with sea salt and freshly ground black pepper, if using.

Heat cast iron skillet (or any heavy-bottomed pan) over high heat until very hot. Add oil to hot skillet. Place scallops in skillet, seasoned side down, ensuring they have enough space to sear without steaming each other. Prepare in batches, if necessary. Sear for about 2 minutes until a golden crust forms. Turn over and cook for about 1 minute more. Remove from heat immediately to avoid overcooking and transfer cooked scallops to clean plate.

To serve, spoon carrot purée onto serving dish and spread. Place 3 seared scallops on top.

Garnish with chopped pistachios and serve.