Bring a large pot of salted water to a boil, then add the pasta and cook until just al dente, about 8 minutes. Drain, reserving a quarter cup of pasta water, and set aside.
While the pasta cooks, heat olive oil in a large deep skillet over medium heat. Add the minced garlic and sauté gently, stirring constantly until fragrant and golden, about 30 seconds.
Add the drained pasta to the skillet with garlic, tossing gently to coat the noodles and warm them through. If the mixture seems dry, splash in a little of the reserved pasta water.
Crumble the feta cheese directly into the hot pasta and stir until the cheese begins to melt and coat the noodles, creating a creamy, tangy sauce.
Add the fresh spinach to the skillet, stirring quickly until it just wilts and turns a vibrant green, about 1-2 minutes. The greens should be tender but still lively in color.
Squeeze fresh lemon juice over the pasta, then season with black pepper to taste. Toss everything together to evenly distribute the flavors.
Remove from heat and let sit for a minute to allow flavors to meld. Taste and adjust seasoning if needed, adding more pepper or lemon juice as desired.
Serve immediately while warm, garnished with extra feta or herbs if you like, enjoying the creamy, vibrant dish that comes together in minutes.
