Fill a large pot with salted water and bring it to a boil. Add the fettuccine and cook as directed on the package until al dente. Drain the pasta and set it aside.
While the pasta is cooking, season the shrimp with salt and pepper.
In a large skillet over medium heat, melt 2 tablespoons of butter with the olive oil. Add the shrimp and cook for 2-3 minutes per side, until pink and opaque. Remove the shrimp from the skillet and set aside.
In the same skillet, melt the remaining 2 tablespoons of butter. Add the minced garlic and sauté until fragrant, about 1 minute. Stir in the heavy cream and bring to a gentle simmer.
Slowly incorporate the Parmesan cheese, whisking until the sauce achieves a smooth and creamy texture. Adjust the flavor with salt and black pepper according to your preference.
Add the cooked fettuccine to the Alfredo sauce and toss to coat evenly.
Return the cooked shrimp to the skillet and gently mix into the pasta and sauce.
Garnish with chopped fresh parsley if desired. Serve immediately.