Bring a large pot of salted water to a boil over high heat. Once boiling, add the 12 oz. fettuccine and cook according to package instructions until al dente, which usually takes about 8-10 minutes. When done, drain the pasta and set it aside, allowing the steam to escape while you prepare the rest of the dish.

In a large skillet, heat 2 tablespoons of vegetable oil over high heat until it shimmers. Season the 1 lb. sirloin steak generously with kosher salt and freshly ground black pepper. Carefully place the steak in the hot skillet, searing for 3-4 minutes on each side until browned and cooked to your desired doneness. Remove the steak from the skillet and let it rest on a cutting board.

In the same skillet used for the steak, lower the heat to medium and melt 2 tablespoons of unsalted butter. Once the butter has melted and begins to bubble, add 2 minced garlic cloves and sauté until fragrant, about 30 seconds. Sprinkle in 2 tablespoons of all-purpose flour, stirring to create a roux, and cook for an additional minute until lightly golden.

Gradually whisk in 2 cups of whole milk, stirring continuously to avoid lumps. Cook the mixture over medium heat for about 5-7 minutes, or until it thickens and coats the back of a spoon.

Once the sauce has thickened, lower the heat, and stir in 1/2 cup of finely grated Parmesan cheese. Continue stirring until the cheese is completely melted and becomes part of the creamy sauce. Taste the sauce and adjust seasoning as needed to enhance the creamy steak fettuccine flavor.

Add the halved 1 1/2 cups cherry tomatoes and 4 cups of baby spinach to the creamy sauce. Stir gently until the spinach wilts, which should take about 2-3 minutes.

Slice the rested steak into thin strips and add it to the skillet with the creamy sauce and cooked fettuccine. Toss everything together gently to combine, allowing the pasta to absorb the flavors. Drizzle with 2 tablespoons of balsamic glaze before serving, and top with finely chopped fresh parsley for a finishing touch.