Preheat the oven to 425° F. In a large skillet over medium heat, cook the olive oil and onions until the onions are soft, 5 minutes. Add the spinach and or kale (I like to use a mix), and mushrooms, and season with salt and pepper. Cook, stirring occasionally until the spinach is wilted, another 10 minutes. Add the butter, garlic, thyme, sage, poultry seasoning, and cayenne.Reduce the heat to low. Mix in the cream cheese, stirring until melted. Add the cream and milk. Simmer for 5 minutes, until the sauce thickens a bit, then remove from the heat. Season with salt and pepper. Spread the wild rice out into a 9x13-inch casserole dish. Pour the spinach and cream sauce over the rice, gently mixing to combine. Top the casserole with Gruyère cheese. Bake 20 to 25 minutes, until the cheese is melted and bubbling on top. Serve with sea salt on top!