Bring a large pot of salted water to a rolling boil, then add the pasta and cook until just al dente, about 8 minutes. Drain, reserving a cup of pasta water, and set aside.
While the pasta cooks, zest the lemon finely using a lemon zester and then juice half of it. Set aside both zest and juice for later.
Heat a large skillet over medium heat and add a tablespoon of butter along with the olive oil. Once melted and fragrant, add the trimmed asparagus pieces and cook for about 3-4 minutes until they develop a slight char and become tender.
Add the minced garlic to the skillet with the asparagus and sauté for about 30 seconds until fragrant and just beginning to brown, stirring constantly to prevent burning.
Stir in the remaining 3 tablespoons of butter, allowing it to melt into the mixture, creating a rich, glossy sauce that coats the asparagus and garlic.
Add the drained pasta to the skillet, tossing gently with tongs to coat it evenly in the butter and asparagus mixture. If the sauce seems thick, splash in a little of the reserved pasta water and stir until it becomes silky and smooth.
Squeeze the lemon juice over the pasta, then sprinkle the lemon zest on top. Season with salt and freshly ground black pepper to taste, tossing everything together to combine.
Transfer the pasta to serving plates, garnishing with extra lemon zest and a few whole asparagus tips for visual appeal. Serve immediately while hot and fragrant.
