Cook's Note: To roast bell peppers, arrange them on a baking sheet and broil, turning occasionally, until the skins are blackened. Transfer the peppers to a bowl, cover and let cool. Peel and seed the peppers.
Preheat the oven to 400 degrees F. Butter a casserole dish with 2 tablespoons butter.
Heat 2 tablespoons butter in a medium saucepan over medium heat. Add the pasta and toast until golden. Stir in the rice and saffron. Add 3 cups stock and bring to boil. Reduce the heat to a simmer, cover and cook until al dente, about 17 minutes. Add an extra 1/2 cup water if the liquid evaporates before the rice is tender.
Meanwhile, season some flour with the paprika in a shallow dish. Sprinkle the chicken with salt and pepper, then dredge in the flour and shake off the excess. Heat 3 tablespoons EVOO in a large skillet or Dutch oven over medium-high heat. Add the chicken and cook until browned and crisp on both sides, 12 to 15 minutes. Transfer the chicken to a paper towel-lined plate to rest.
Add 1 tablespoon EVOO to the skillet, then add the chorizo and cook until the fat begins to render, about 2 minutes. Add the garlic and onions and cook until soft, about 5 minutes. Deglaze with a splash of sherry, stirring and scraping up any browned bits from the bottom of the skillet with a wooden spoon. Stir in the peas, thyme and roasted peppers and immediately remove from the heat.
Slice the chicken and combine with the rice mixture and chorizo-pepper mixture. Transfer to the prepared casserole dish. Bake until heated through and the bottom is crisp, 30 to 40 minutes. Add a splash of stock, about 1/2 cup, if the top of the casserole dries out too much.
Meanwhile, cover the fish with about 1/2 cup kosher salt and let stand for 10 minutes. Rinse and pat dry. Season some flour with seafood seasoning in a small dish. Lightly dredge the fish in the flour and shake off the excess. Heat the remaining 1 tablespoon EVOO in a skillet over medium-high heat. Add the fish and cook until firm and opaque, 5 to 6 minutes, turning once. Transfer the fish to a plate. Add the shrimp to the skillet and cook until pink, 4 to 5 minutes. Add the lemon juice and 1/2 cup sherry, then swirl in the remaining 1 tablespoon butter until melted. Add the parsley.
Flake the fish into pieces. Top the casserole with the fish, shrimp and sherry sauce. Divide among plates.
Cook's Notes: Always buy seafood within 24 hours of serving.
Quick-salting cod with salt is a technique of NYC chef George Mendez. It gives the fish a firmer texture and more pronounced flavor.
The casserole can be covered and refrigerated before baking for a make-ahead meal.