Method

Cook pasta in a large pot of salted water, occasionally stirring, until al dente. Drain pasta, reserving 1½ cups pasta cooking liquid.

Meanwhile, heat oil in a large Dutch oven or heavy pot over medium-high until shimmering. Add asparagus, season with salt, and cook, often stirring, until just beginning to take on color, about 1 minute. Add garlic, lemon zest, and red pepper flakes and cook until fragrant, about 30 seconds. Remove from heat and let sit until pasta is done.

Add pasta and basil to the pot with the asparagus mixture and return to medium-high heat. Squeeze juice from both lemons into the pot and add 2 oz. Parmesan and 1 cup reserved pasta cooking liquid. Cook, tossing vigorously and adding more pasta cooking liquid if needed until sauce is creamy and emulsified and pasta is coated, about 1 minute. Taste and season with more salt if needed. Remove and discard garlic.

Divide pasta among bowls, place a lemon strip, and top with more Parmesan.