Heat a large nonstick skillet or large sauté pan over medium heat, add the oil and heat through. Add the zucchini, working in batches if needed so as not to overcrowd the pan. Sauté, until the zucchini is tender, about 4 minutes. Season with salt and pepper and remove the cooked squash to a bowl and set aside, continuing with the remaining zucchini if needed.

Bring a large pot of salted water to a boil. Add the fettuccine and cook, stirring occasionally, until al dente, about 6 to 8 minutes. Reserve ½ cup of the pasta cooking water then drain the noodles and return them to the pot.

Add the butter and squeeze the lemons over the pasta, adding the squeezed lemon halves to the pot and tossing to combine until the butter has melted.

Add the zucchini to the pasta and toss once more, adding about ¼ cup of the pasta cooking water if needed.