- Bring large pot of water to a boil. Drop gnocchi into water and stir gently.
- Meanwhile, sweat garlic and shallot in olive oil, then season with salt and pepper. Add corn, crawfish, mustard greens, and tomatoes to pan.
- Remove gnocchi from water (they are done when they float and are light and airy), and add to pan with a few ladles of stock. Season to taste with salt and pepper.
- Preheat oven to 375 degrees.
- Roast potatoes in oven until soft. Let cool.
- Peel potatoes, and pass through ricer or food mill. Form a well in potatoes, and season with salt, cheese and nutmeg. Then add egg and yolk to center of well and begin to slowly beat into potatoes. Sprinkle half of flour on top of potatoes, and press and fold into potatoes until dough comes together and is no longer tacky. Do not knead dough. It should feel firm but yielding.
- Cut dough into 8 pieces and roll each piece into ½-inch diameter ropes, dusting with flour as you go. Cut ropes into ½-inch pieces.
- Preheat oven to 350 degrees.
- Place gumbo crabs in roasting pan and roast for 20 minutes.
- In the meantime, sweat onion, carrot and celery in a little olive oil in Add tomato paste, and cook for 3 minutes, then add white wine, and cook for 5 minutes. Add gumbo crabs, cover with water, and add rest of ingredients. Simmer 1½ hours.