Using two sauce pans, put some water on to boil the spaghetti and the shrimp.
Make the Gremolata: In the bowl of a small food chopper, add the garlic. Pulse about 5 times or until rough chopped. Add parsley leaves and the zest of 1 lemon. Pulse about 20 times until medium chopped.
Juice the lemon into a large bowl. Whisk in the crème fraîche and olive oil until combined. Add the Parmesan, red-pepper flakes and reserved gremolata; mix until combined. Set aside.
Cook the Angel Hair Pasta according to package directions. Drain, reserving about 1/2 cup of the pasta water before draining.
Cook the Shrimp: Peel, devein, remove tails. In a sauce pan with water, add a few leaves of parsley and the lemon that you've used to zest and juice. Let this mixture boil for 5 minutes and then add the shrimp and cook for two minutes. Remove shrimp to a plate and set aside. Keep warm.
Transfer the pasta to the bowl with the sauce. Add the sauce and toss to coat the noodles evenly, adding pasta water 1 tablespoon at a time to thin sauce if needed.
Transfer the pasta to individual plates. Add 4 shrimp per plate and garnish with additional Parmesan, a drizzle of olive oil and parsley. Serve immediately.