Boil the Pasta
Bring a large pot of heavily salted water to a boil. Add your pasta and cook until al dente (usually 1–2 minutes less than the package directions).
Critical Step: Before draining, scoop out 1 cup of starchy pasta water and set it aside. Drain the pasta and set aside.
Sear the Seafood
In a large skillet or deep pan, heat the olive oil and butter over medium-high heat. Add the shrimp and lobster chunks in a single layer. Sauté for 2–3 minutes until the shrimp are pink and the lobster is opaque. Remove the seafood with a slotted spoon and set aside on a plate to prevent overcooking.
Build the Garlic Base
Lower the heat to medium. In the same pan (don't wash out those seafood juices!), add the minced garlic and red pepper flakes. Sauté for 1 minute until fragrant but not browned.
Simmer the Sauce
Pour in the heavy cream and bring to a very gentle simmer. Slowly whisk in the Parmesan cheese, a handful at a time, until the sauce is smooth and slightly thickened. Season with salt and black pepper.
The Great Merge
Add the cooked pasta and the cooked seafood back into the skillet. Toss everything together using tongs. If the sauce is too thick, add your reserved pasta water 2 tablespoons at a time until it reaches a silky, velvety consistency.
The Mediterranean Finish
Remove from heat. Fold in the lemon zest, a squeeze of lemon juice, and the fresh parsley. Toss one last time and serve immediately.