Bring a large pot of salted water to a rolling boil and cook the pasta until just al dente, about 8-10 minutes. Drain, reserving a cup of pasta water, and set aside.
While the pasta cooks, heat a large sauté pan over medium heat and add the olive oil. Once shimmering, add the finely chopped garlic and cook until fragrant, about 30 seconds, until it releases a spicy aroma.
Add the fresh spinach to the pan in batches if needed, stirring gently until it wilts and turns bright green, about 2 minutes. It should be tender but still vibrant.
Reduce the heat to low and crumble in the feta cheese. Stir gently until the feta begins to melt into a creamy coating, about 1-2 minutes. If it seems thick, add a splash of the reserved pasta water to loosen it up.
Add the drained pasta to the pan, tossing gently with tongs to coat it evenly in the feta and spinach mixture. If needed, add more of the reserved pasta water to create a silky sauce that clings to every strand.
Finish by squeezing fresh lemon juice over the pasta and cracking black pepper to taste. Toss again to combine everything thoroughly.
Serve immediately in warm bowls, garnished with extra feta or a drizzle of olive oil if desired. Enjoy the vibrant, creamy flavors in every bite!
