In your large skillet, combine the pasta, shrimp, minced garlic, lemon zest, olive oil, butter, red pepper flakes, and 3 cups of cold water.
Bring the mixture to a boil over high heat. Keep an eye on it and stir occasionally to prevent the pasta from sticking.
Reduce the heat to medium and cook, stirring frequently, until the pasta is al dente and the shrimp is pink and cooked through. This should take about 9-11 minutes.
If the pasta has absorbed all the water before it's fully cooked, add a little more water, about 1/4 cup at a time.
Once the pasta is al dente and most of the water has evaporated, remove the pan from heat. The sauce should be creamy and coat the pasta.
Stir in the lemon juice, chopped parsley, and Parmesan cheese. Season with salt and pepper to taste.
Let the dish sit for a couple of minutes to allow the sauce to thicken slightly.