Heat a large pot over medium heat. Drizzle with a 2-count of oil, add the butter, and stir it around so it melts. Saute the onion and garlic until soft, about 5 minutes. Add the spinach in batches, pushing it down with a wooden spoon to help it wilt. Keep adding more spinach when there is room in the pot. Cook the spinach until it is dry, then lower the heat and add the cream and nutmeg. Stir and cook for 10 minutes. Season with salt and pepper and serve hot.