Bring a large pot of salted water to a boil. Add the linguine or spaghetti and cook according to package instructions until al dente. Reserve about 1 cup of the pasta cooking water, then drain and set the pasta aside.
In a large skillet over medium heat, melt the butter and add the olive oil. Once hot, add the minced garlic and red pepper flakes. Sauté for about 30 seconds until fragrant but not browned.
Add the shrimp to the skillet in a single layer. Season with salt and pepper. Cook for 2-3 minutes on one side until they turn pink, then flip and cook for an additional 1-2 minutes until fully cooked.
Add the cooked pasta to the skillet with the shrimp. Pour in the lemon juice and zest, and toss to combine. If the mixture seems dry, add a little of the reserved pasta water to create a saucy consistency.
Remove from heat and taste to adjust seasoning if necessary. Garnish with fresh chopped parsley and serve hot. Optionally, sprinkle with grated Parmesan cheese for extra flavor.
Notes
Adjust red pepper flakes to taste for desired spiciness.