The lobster in this seafood pasta really knocks it out of the park. You can find frozen or fresh cooked lobster meat at most fishmongers, but it if not you can buy 2 small tails and steam them until they are just cooked. It is worth the effort to in order elevate this decadent dinner.
Bring a large pot of salted water to a boil. Cook the pasta to al dente according to package instructions, about 8 minutes. Reserve 1 cup of the pasta water, then drain and reserve.
Heat the oil in large heavy-bottomed pot over high heat until shimmering. Add the garlic and red pepper flakes if using. Lower the heat and cook until the garlic is starting to turn golden, about 1 minute. Add the clams, mussels and white wine and cover. Cook until the shells start to open. As they open transfer them to a bowl with tongs. The mussels will cook faster than the clams but in all it should take 6 to 10 minutes (discard any that do not open). Add the tomato puree to the pot and bring to a boil. Reduce to a simmer and cook until slightly reduced, about 5 minutes.
Add the pasta to the sauce and cook until hot, about 2 minutes. If the sauce gets too thick, add the reserved pasta water 1/4 cup at a time until saucy. Stir in the lobster, mussels, clams and any broth from the bottom of the bowl and stir to get everything hot, about 2 minutes. Finish with the lemon zest. Divide between bowls and top with the basil and Parmesan.