Now it’s time for the fun part! Add the grated Parmesan cheese, softened cream cheese, chopped spinach, and freshly squeezed lemon juice into the pot. Stir everything well until fully combined. You’ll see the spinach wilt and the cheese melt, creating a luscious, creamy texture. Cover the pot for a few minutes to let it thicken up. It will seem a bit soup-like at first, but don’t worry—the pasta will absorb some of that sauce as it sits.