In a large pot, bring salted water to a boil. Add the fettuccine and cook according to package instructions until al dente. Reserve 1/2 cup of pasta water, then drain the pasta and set aside.
In a large skillet over medium heat, add olive oil and butter. Once melted, add the minced garlic and sauté for about 30 seconds until fragrant.
Place the shrimp in the skillet. Season with salt, pepper, and optional red pepper flakes. Cook for 2-3 minutes on each side until the shrimp turn pink and opaque. Remove the shrimp from the skillet and set aside.
In the same skillet, add the chicken or vegetable broth and bring to a simmer. Reduce the heat and stir in the heavy cream. Let it simmer for about 2-3 minutes, stirring occasionally, until the sauce thickens slightly.
Add the cooked pasta and shrimp back into the skillet. Stir well to coat everything in the creamy sauce. If the sauce is too thick, gradually add reserved pasta water until the desired consistency is reached.
Stir in the grated Parmesan cheese until fully melted and mixed into the sauce. Taste and adjust seasoning if necessary.
Plate the pasta, ensuring an even distribution of shrimp, then garnish with fresh parsley for a pop of color.
Notes
Serve in shallow bowls with extra parsley and Parmesan. Crusty bread pairs well.