Bring a large pot of salted water to a boil. Meanwhile, season the shrimp with salt and pepper.
In a large saute pan, heat the olive oil over medium-high heat. Add the shrimp and cook, without moving them around, for 2 to 3 minutes, until nicely pink and starting to brown on the edges. Use a spatula to flip and cook the other sides for another 2 to 3 minutes, until fully cooked, slightly curled, and bright pink. Set aside on a plate.
In the same pan, sauté the onion, garlic, lemon zest, and red pepper flakes until the onions are translucent.
Once done, add flour allow to cook the 5 minutes.
Add the water, lemon juice and ¾ tsp salt and a pinch of black pepper.
Simmer until slightly thickened, about 10 minutes. While the sauce is simmering, cook the pasta. Drain and return to pot.
Return the shrimp to the sauce just to warm through, about 2 minutes.
Add the cooked pasta to the sauce and stir around until all the pasta is well-coated with the sauce.
Top with crumbled feta cheese (optional). Serve.
Servings 0