Bring a large pot of salted water to a rolling boil. Add the pasta and cook until just al dente, about 8 minutes. Drain and set aside.
While the pasta cooks, peel and devein the shrimp if needed. Pat them dry with paper towels and set aside.
Heat your skillet over medium-high heat and add 2 tablespoons of olive oil. Once shimmering, add the sliced garlic and cook for about 30 seconds until fragrant and just beginning to turn golden, releasing a warm, pungent aroma.
Add the shrimp to the skillet. Cook for 2-3 minutes on each side, until they turn a bright pink and develop a slight caramelized edge. They should be opaque and firm to the touch.
Remove the shrimp from the skillet and set aside. In the same pan, add the remaining 2 tablespoons of olive oil if needed, along with a pinch of red pepper flakes for a gentle heat.
Add the drained pasta to the skillet, tossing to coat in the garlic oil. Let it cook for about 1 minute, allowing the flavors to mingle and the pasta to warm through.
Sprinkle the fresh spinach over the pasta. Quickly toss and stir vigorously until the spinach wilts, about 30 seconds; it should turn a vibrant green and soften without overcooking.
Return the cooked shrimp to the skillet and toss everything together. Cook for another 30 seconds to reheat and combine the flavors. Squeeze in lemon juice, and add lemon zest for brightness, stirring well.
Season with salt and pepper to taste. Give the mixture a final toss, ensuring everything is heated evenly and coated with the flavorful oil and lemon zest.
Serve the pasta hot, garnished with extra lemon zest or herbs if desired. Enjoy the dish immediately while the shrimp are tender and the greens are bright.
