Bring a large pot of salted water to a boil. Cook the spaghetti until al dente, according to package directions. Reserve ½ cup of pasta water, then drain.
Sear the steak.
Heat 1 tablespoon of olive oil in a large skillet over medium-high heat. Add steak slices, season lightly with salt and pepper, and cook for 2–3 minutes per side until just browned. Transfer to a plate and set aside.
Cook the shrimp.
In the same skillet, add the remaining olive oil. Sear shrimp for 1–2 minutes per side, until pink and cooked through. Remove and set aside with the steak.
Build the sauce.
Lower the heat to medium. Add garlic and red pepper flakes to the skillet, cooking until fragrant (about 30 seconds). Add cherry tomatoes and cook until they start to burst and release their juices, about 4 minutes.
Deglaze and finish.
Pour in the white wine (or broth) and scrape up any browned bits. Let it simmer for 2 minutes, then stir in the butter.
Bring it all together.
Add the cooked pasta, shrimp, and steak back to the pan. Toss to coat, adding a splash of the reserved pasta water until the sauce lightly clings to the noodles.
Season and serve.
Stir in parsley and lemon juice. Taste and adjust seasoning as needed. Serve warm with grated Parmesan and extra herbs on top.
Notes
Helpful Tips
Keep shrimp the star: A little steak goes a long way — it adds flavor without taking over.
Add color: Mix in baby spinach or roasted red peppers before serving.
Skip the wine: Broth or a splash of lemon juice works just as well for deglazing.
Make it creamy: Stir in a tablespoon of mascarpone or a splash of cream for a cozy twist.