Bring a large pot of generously salted water to a rolling boil. Add the linguine and cook according to package directions until al dente. Before draining, reserve 1 cup of the starchy pasta water. Drain the pasta and set aside.

While the pasta cooks, heat the olive oil in a large skillet or non-stick pan over medium heat. Add the trimmed asparagus pieces and sauté for 3-5 minutes, until they are tender-crisp and bright green. Add the minced garlic and red pepper flakes (if using), and cook for another 1 minute until fragrant, being careful not to burn the garlic.

Pour in the vegetable broth and fresh lemon juice into the skillet. Bring to a gentle simmer and cook for 2-3 minutes, allowing the liquid to reduce slightly and the flavors to meld.

Add the cooked and drained pasta to the skillet with the asparagus and lemon sauce. Stir in the lemon zest and grated Parmesan cheese. Toss everything together, adding a splash or two of the reserved pasta water as needed to create a light, cohesive sauce that coats the pasta.

Season the pasta with salt and freshly ground black pepper to taste. Divide the lemon asparagus pasta among serving bowls, garnish with fresh chopped parsley and additional grated Parmesan cheese, if desired. Serve immediately.