Bring a large pot of salted water to a boil. Add the pasta and cook according to the package instructions until al dente. Reserve about 1 cup of pasta water before draining the pasta.
In a large skillet, melt 2 tablespoons of butter over medium-high heat. Add the steak bites in a single layer. Season with salt and pepper. Cook for 3-4 minutes until browned on all sides and cooked to your desired doneness. Remove the steak from the skillet and set aside.
In the same skillet, add the remaining 2 tablespoons of butter and the minced garlic. Cook for about 1 minute until fragrant.
Lower the heat to medium and add the heavy cream, stirring to combine. Gradually whisk in the grated Parmesan cheese, garlic powder, salt, and pepper. Allow the sauce to simmer for 2-3 minutes until it thickens slightly.
Add the cooked pasta to the skillet and toss to coat in the creamy Parmesan sauce. If the sauce is too thick, gradually add reserved pasta water until you reach the desired consistency.
Return the steak bites back to the skillet, tossing them with the pasta and creamy sauce. Cook for an additional minute just to heat through.
Remove from heat, garnish with chopped parsley, and serve immediately.