Begin by cooking the pasta according to package directions until al dente. Reserve about 1 cup of pasta water, then drain the pasta and set aside.
In a large skillet over medium heat, add the butter and olive oil. Let the butter melt and mix with the olive oil.
Once the butter is melted, add the minced garlic and red pepper flakes. Sauté for 1-2 minutes until the garlic is fragrant and slightly golden, being careful not to burn it.
Add the shrimp to the skillet and season with salt and pepper. Cook for 2-3 minutes, flipping halfway, until the shrimp turn pink and opaque.
Pour in the lemon juice and stir in the lemon zest, allowing the flavors to combine for another minute.
Add the drained pasta to the skillet and toss well to coat the noodles in the garlic butter sauce. If the mixture seems dry, add reserved pasta water a little at a time until the desired consistency is reached.
Stir in the fresh parsley, mixing everything together. Adjust seasoning with more salt, pepper, or lemon juice if desired.
Serve the dish hot, topped with grated Parmesan cheese if using, and an extra sprinkle of parsley for garnish.
Notes
Adjust red pepper flakes to taste for spice preference.