Fill large pot with water and add the whole lemon to the water. Remove zest from about 1/2 of the whole lemon and set the zest aside for the sauce. Add zested whole lemon to the water and bring the water with the lemon to a boil over high heat. Once boiling remove lemon and set aside to cool. Add salt to your water, then add pasta and cook to al dente according to package directions.
Meanwhile, stir together the sauce ingredients in a small bowl. Prepare your spinach and set aside. When lemon is cool enough to handle, cut in half and juice. Pour juice through a strainer in to a small bowl, to remove seeds and pulp. Set aside.
When pasta is cooked, before draining, remove 1 cup of the pasta water and set aside. Drain pasta well and return to the pot. Add sauce mixture and spinach to the pot with the hot pasta and with tongs, toss well until the spinach is wilted and sauce is coating the pasta. Drizzle with reserved lemon juice and toss well. If pasta seems tight (clumpy/sticking together), add a bit of your reserved pasta water to the pasta and toss to loosen it up. Season with salt and freshly ground pepper, to taste. Serve with additional freshly grated Parmesan and more freshly ground pepper.
To measure dried linguine or other long, dried pasta for 2 servings, aim for a 2 -inch diameter circle of dried pasta for an average serving or up to 3-inches for a hearty appetite.Be sure to read the “Ingredient and Cook's Notes" (above the recipe card!), where I share more detailedtips, variations and substitution suggestions for this recipe!