How to Make It
Bring stock and 5 parsley stems to a simmer in a medium saucepan over medium; reduce heat to low, and keep warm. Chop parsley leaves to equal 5 tablespoons; reserve remaining leaves for another use. Place chopped parsley leaves in a small bowl, and set aside.
Heat 3 tablespoons oil in a large saucepan over medium. Add onion and 1 tablespoon garlic; cook, stirring often, until onion is softened, about 3 minutes. Stir in rice, and cook, stirring often, until grains are almost translucent and have a nutty aroma, about 3 minutes. Increase heat to medium-high. Add wine, and cook, stirring constantly, until wine is absorbed, 2 to 3 minutes.
Remove and discard parsley stems from warm stock. Add 1/4 cup stock to rice mixture, and cook, stirring often, until almost absorbed. Continue adding 2 to 3 cups stock, 1/4 cup at a time, stirring often, until stock is almost absorbed after each addition and rice is just beginning to soften, about 15 minutes total. Remove from heat, and set aside.
Heat remaining 3 tablespoons oil in a large skillet over medium-high. Add langoustines and clams; cook, turning occasionally, until langoustines are pink and just cooked, 5 to 7 minutes. Remove and set aside. Continue cooking clams until they open, about 10 minutes, stirring in squid and remaining 1 teaspoon garlic during last minute of cooking time. Remove from heat; discard any unopened clams. Return langoustines to skillet.
Return rice mixture to heat over medium. Stir in cuttlefish ink, lemon zest, and salt. Continue adding stock, 1/4 cup at a time, stirring often, until stock is almost absorbed after each addition, rice is al dente, and mixture is creamy, 5 to 7 minutes longer. (You may not need all remaining stock.) Remove from heat. Stir in butter, lemon juice, and 3 tablespoons reserved chopped parsley. Season to taste with salt. Divide risotto among 4 bowls, and top evenly with langoustines, clams, squid, and remaining 2 tablespoons chopped parsley. Serve immediately with lemon wedges.