Preheat oven to 350°F. Spray or grease a 3-quart baking dish with coconut oil.
Cook sausage in heavy large skillet over medium-high heat until brown, breaking into small pieces with a spoon or spatula, about 5 minutes.
While sausage cooks, make cashew cream. Put ¾-cup raw cashews in a 2-cup measuring cup. Pour enough warm or hot water over cashews to fill measuring cup. Let cashews sit in water while cooking sausage, then blend cashews and water in a blender on high speed until completely smooth.
Sprinkle arrowroot over sausage, stirring to coat, then add in 1 ½ cups cashew cream (or 1 ½ cups coconut milk/cream, whisked). Cook until mixture thickens and comes to boil, stirring occasionally, about 3-5 minutes. Add plenty of fresh black pepper.
In a medium bowl, whisk eggs and add remaining cashew cream (or coconut milk/cream), spices, salt, and ⅓ of the green onions.
In a baking dish, spread hashbrowns evenly, and sprinkle with a pinch of salt. Top with ⅓ of green onions, then sausage mixture, then egg mixture. Bake 45-50 minutes then sprinkle with remaining green onions. A knife inserted in the center won't come out clean because of the creamy sauce, but the surface should be firm.
Cut into squares and serve.