How to Make It
In a small bowl, combine 1/4 cup of the wine with the saffron and let stand to infuse.
Preheat the oven to 350°. In a medium saucepan, cover the potatoes with water and bring to a boil. Cook over moderately high heat until just tender, about 15 minutes, then drain. Peel and slice the potatoes 1/3 inch thick.
In a large, deep skillet, heat 3 tablespoons of the olive oil until shimmering. Add the potatoes in a single layer and cook over high heat, turning once, until golden brown, about 3 minutes per side. Season the potatoes with salt and pepper and, using a slotted spoon, transfer to a plate; keep warm.
Wipe out the skillet, then heat 2 tablespoons of the olive oil. Season the lobster with salt and pepper and cook, cut side down, over moderately high heat until the meat is golden brown, about 3 minutes. Turn and cook until the shells start to turn red, about 2 minutes. Transfer the lobster to a large bowl. Add the remaining 2 tablespoons of olive oil and, when it's hot, add the squid. Cook over high heat, stirring once, until the squid is just tender, about 3 minutes. Using a slotted spoon, transfer the squid to the large bowl.
Add the tomatoes and crushed red pepper to the skillet and cook over high heat until the tomatoes start to soften, about 1 minute. Add the remaining 3/4 cup of wine and boil until reduced by half, about 3 minutes. Return the lobster to the skillet, cut side up, and add the clams, mussels, shrimp and snapper. Add 1/4 cup of water and season with salt and pepper. Cover and cook over moderate heat. After 2 minutes, start checking under the lid: As the shrimp and fish turn opaque and the mussels and clams open, transfer them to the large bowl. Discard any shellfish that do not open. Remove the skillet from the heat.
Fill a small saucepan halfway with water and bring to a simmer over low heat. In a medium bowl, whisk the yolks with the saffron-infused wine over the simmering water until pale yellow, fluffy and hot, about 3 minutes. Season with salt and pepper.
Season the seafood juices with salt and pepper and return all of the seafood to the skillet, stirring to coat with the juices. Arrange the fried potatoes in shallow bowls. Using a slotted spoon, transfer the seafood to the bowls. Pour the juices over the seafood and spoon a dollop of the saffron zabaglione on top. Serve with the toasts.