Bring a large pot of salted water to a boil. Add pasta and cook according to package instructions until al dente. Reserve 1 cup of pasta water and drain the rest.
In a large skillet over medium heat, melt the butter and add olive oil. Once hot, add minced garlic and red pepper flakes, sautéing for about 1 minute until fragrant.
Add the shrimp to the skillet, season with salt and pepper, and cook for about 2-3 minutes on each side until shrimp are pink and cooked through.
Add the lemon juice and zest to the pan, stirring to combine and deglaze any browned bits from the bottom.
Toss the cooked pasta into the skillet along with half of the reserved pasta water. Stir well to combine, adding more pasta water as needed to create a light sauce that coats the pasta.
Remove from heat and stir in chopped parsley for freshness.
Adjust seasoning as necessary and serve hot with grated Parmesan cheese on top, if desired.
Notes
Adjust red pepper flakes to taste for desired spiciness.