Bring a large pot of salted water to a boil and cook the pasta until al dente, about 8 minutes. Drain, reserving ½ cup of cooking water, and set aside.
Trim the woody ends off the asparagus and slice into 2-inch pieces, keeping the tips whole for visual appeal.
In a large sauté pan, melt the butter over medium heat until it begins to foam and smells nutty, about 1 minute.
Add the minced garlic to the pan and sauté until fragrant, about 30 seconds, stirring constantly to prevent burning.
Stir in the asparagus and sauté until tender but still vibrant green, about 3-4 minutes. The tips should slightly caramelize and become fragrant.
Add the drained pasta to the pan with the asparagus, tossing to coat evenly in the buttery garlic mixture.
Zest the lemon directly into the pan, then squeeze in the lemon juice. Quickly stir to combine, allowing the bright citrus aroma to infuse the dish.
If the sauce feels thick, add a splash of the reserved pasta water, stirring until silky and well-coated. Season with salt and pepper to taste.
Remove from heat and sprinkle with freshly grated Parmesan, if using. Toss gently to distribute the cheese evenly.
Serve immediately, garnished with extra lemon zest or Parmesan if desired, and enjoy the vibrant, buttery flavors.
