Bring a large pot of salted water to a boil and cook the spaghetti until al dente, about 8–10 minutes. Drain, toss with olive oil, and set aside.
Heat olive oil in a skillet over medium-high heat, sear the steak strips for 2–3 minutes per side until browned, then set aside.
Reduce heat to medium, sauté minced garlic for a minute until fragrant.
Pour in heavy cream, bring to a gentle simmer, and stir in Parmesan until smooth.
Add the spaghetti and steak, toss to coat, and season with salt and pepper.
If the sauce is too thick, add a splash of pasta water. Garnish with parsley and serve warm.