Bring a large pot of salted water to a boil and cook the linguine according to package directions until al dente. Reserve 1/2 cup of pasta water, then drain the pasta.

While the pasta cooks, heat the olive oil in a large skillet over medium heat. Add the minced garlic and red pepper flakes and cook for 30 seconds until fragrant.

Add the shrimp to the skillet in a single layer. Season with salt and black pepper. Cook for 2 minutes per side until the shrimp turn pink and opaque.

Zest one lemon directly into the skillet, then squeeze in the juice of both lemons. Stir in the spinach and cook for 1 minute until it wilts.

Add the drained pasta to the skillet along with a splash of the reserved pasta water. Toss everything together until the noodles are coated in the sauce.

Remove the skillet from the heat and stir in the grated Parmesan cheese. Taste and adjust salt and pepper if needed before serving.