Combine ½ teaspoon salt, cayenne and garlic powder and rub the shrimp with it. Heat olive oil in a skillet over medium heat. Saute the shrimp for 3 minutes. Add the onions, celery and garlic and sauté for 2 or 3 more minutes. Add the pernod and cook for 1 minute. Add the parsley and cream and bring to a boil. Season to taste.
For the Spinach Cake
Heat the butter in a skillet over medium-high heat. Add ¼ cup of flour. Stir constantly for 5 to 6 minutes to make a blond roux the color of sandpaper. Add the onions and cook, stirring for about 2 minutes until slightly wilted. Add the milk and stir until the mixture thickens. Add the spinach, salt, cayenne, pepper, nutmeg and garlic and cook stirring for about 4 minutes. Remove from heat. Add bread crumbs, parmigiano reggiano, and Pernod and mix well. Let cool for about 30 minutes.
Divide the mixture into 4 equal portions and shape into patties. Heat the oil in a non-stick skillet over medium high heat. Combine the remaining ¼ cup flour and the rub. Dredge the patties, coating evenly in the flour. Fry the cakes for about 2 minutes on each side until golden. Transfer to a warm platter. Spoon shrimp and sauce over the cakes and serve.