How to Make It
In a large pot, bring the chicken stock to a boil over moderately high heat. Add the spinach, cover and cook for 1 minute. Toss the spinach with tongs, cover and cook for 1 minute longer, until just wilted. Drain the spinach and let cool, then squeeze out as much liquid as possible.
In a large, shallow pot, cook the butter, shallots and garlic over moderate heat, stirring occasionally, until soft and translucent but not browned, about 5 minutes. Remove the pot from the heat and add the Cognac and Pernod. Carefully tilt the pan over the burner to ignite the alcohol; cook until the flames subside. (Alternatively, remove the pan from the heat and ignite with a long match, then return to the heat.) Stir in the drained spinach, cream and thyme. Bring to a boil and cook, stirring, until thickened, about 2 minutes. Discard the thyme sprigs. Season with a pinch of nutmeg, salt and white pepper and transfer to a bowl. Serve the creamed spinach hot.