Bring a large pot of salted water to a rolling boil, then add your pasta and cook until just al dente, about 8-10 minutes. Stir occasionally, and once done, drain, reserving about 1/4 cup of the pasta water.
While the pasta cooks, prepare the asparagus by trimming the woody ends and cutting into 2-inch pieces. Heat a skillet over medium heat, add a splash of olive oil, and sauté the asparagus for 3-4 minutes until vibrant green and slightly tender with some caramelized edges.
Push the asparagus to one side of the skillet, then add the melted butter to the empty side. Let it melt gently, filling the kitchen with a nutty aroma. Toss in the minced garlic and sauté for about 30 seconds until fragrant, but do not let it brown.
Add the drained pasta directly into the skillet with the asparagus and butter mixture. Toss everything together to coat the pasta evenly in the buttery sauce. Grate the lemon zest over the pasta and squeeze in half of the lemon juice, stirring to combine.
Loosen the sauce by adding a splash of the reserved pasta water, about 1/4 cup, stirring well until the sauce becomes glossy and clings beautifully to the pasta. Taste and season with salt and freshly ground black pepper as needed.
Finish by squeezing the remaining lemon juice over the pasta for extra brightness. Give everything a final toss, then remove from heat. Serve immediately, garnished with extra lemon zest or herbs if desired.
