Bring a large pot of salted water to a rolling boil and cook the pasta until just al dente, about 8-10 minutes. Drain and set aside.
While the pasta cooks, heat a deep skillet over medium heat and add the olive oil, letting it shimmer and smell fruity and fragrant.
Add the minced garlic to the skillet and sauté gently, stirring constantly, until fragrant and golden around the edges—about 30 seconds to 1 minute.
Drop the frozen spinach directly into the skillet and stir vigorously until it thaws and wilts, about 3-4 minutes. The spinach should turn bright green and fragrant.
Add the cooked pasta to the skillet with the spinach, tossing everything together to coat evenly. If it looks too dry, splash in a little reserved pasta water or water.
Stir in the nutritional yeast and squeeze the lemon half over the mixture, then season with salt and pepper. Toss gently until everything is coated and heated through, about 1-2 minutes.
Remove from heat, drizzle with a little extra olive oil if desired, and give everything a final toss. Let sit for a minute so flavors meld.
Serve immediately in warm bowls, garnished with extra lemon zest or herbs if you like. Enjoy the velvety, vibrant green pasta right away.
