Finely cut squid and shrimp give this elegant dish from Australian chef Mark Best of Marque restaurant its risotto-like texture, while a garnish of curry leaves adds some flavorful spice.
Place squid bodies on a baking sheet; transfer to freezer and freeze for 1 hour. Transfer tentacles to refrigerator until ready to use.
Meanwhile, place cauliflower in a medium-heavy-bottomed saucepan and add milk; season with salt and pepper. Cover with a parchment paper round to keep cauliflower submerged. Place saucepan over low heat and cook until tender, 30 to 40 minutes. Drain cauliflower, reserving milk, and transfer to jar of a blender. Blend until smooth, adding some of the milk as necessary to puree. Season with salt and pepper and set aside.
Fill a large heavy-bottomed saucepan 1-inch high with vegetable oil; heat over medium-high heat until it reaches 350 degrees on a deep-fry thermometer. Add curry leaves and cook until they stop popping, 10 to 20 seconds. Transfer to a paper-towel-lined plate to drain.
Heat 1 tablespoon olive oil in a large heavy-bottomed skillet over high heat. Add shrimp and cook, turning, until opaque, 2 to 3 minutes. Remove from skillet, set aside and keep warm. Add remaining tablespoon olive oil to skillet and add reserved squid tentacles; cook, turning, until opaque, 2 to 3 minutes. Set aside and keep warm.
Remove squid bodies from freezer and cut into 1/4-inch pieces. Add 3 tablespoons butter to a medium saucepan over medium heat. When butter is melted and foamy, add cut squid, 5 heaping tablespoons cauliflower puree (reserve any remaining for another use), and leeks; season with salt and pepper. Cook, stirring, until squid becomes opaque, 2 to 3 minutes. Add remaining tablespoon butter and cook, stirring, until melted; season with salt and pepper.
Divide squid mixture evenly between six serving bowls. Divide shrimp and curry leaves evenly between the bowls. Using an immersion blender, blend shrimp broth until frothy; spoon broth into each bowl. Garnish with squid tentacles and serve immediately.