How to Make It
Bring a large saucepan of water to a boil. Add the rice and cook, stirring a few times, until just al dente, 16 minutes. Drain well.
Meanwhile, in a medium saucepan, heat the oil. Add the shrimp shells; cook over moderately high heat, stirring often, until beginning to brown, about 3 minutes. Add the chopped fennel, onion, celery, carrot, garlic, fennel seeds and Aleppo pepper and cook over moderately high heat, stirring often, until the onion is golden, about 6 minutes. Add the wine and boil until almost evaporated. Add 2 cups of the chicken stock and simmer over moderate heat for 12 minutes. Strain.
In another medium saucepan, combine the cream with the saffron, 1/2 cup of the shrimp stock and the remaining 1 cup of chicken stock and bring to a simmer. Add the parboiled rice and cook over moderate heat, stirring, until the sauce has thickened and the grains are tender, about 3 minutes. Season with salt and black pepper, cover and remove from the heat.
In a large skillet, bring the remaining shrimp stock to a simmer. Add the shrimp and cook over moderately low heat, turning once, until pink and curled, about 3 minutes. Remove the skillet from the heat and stir in 4 tablespoons of the butter, 1 tablespoon at a time. Season with salt and black pepper.
In a small bowl, toss the sliced fennel and scallion with the lemon juice and season with salt and black pepper.
Rewarm the rice and stir in the remaining 1 tablespoon of butter. Transfer the rice to shallow bowls. Spoon the shrimp and sauce over the rice. Top with the fennel salad, garnish with the thyme and serve.