Heat the vegetable broth in a saucepan until simmering, then lower the heat to keep it warm on low.
Trim the woody ends from the asparagus, then chop the stalks into 2-3 cm pieces, setting aside a few whole tips for garnish if desired.
In your large pan, heat olive oil over medium heat until shimmering. Add the arborio rice and stir for about 2 minutes, until the grains turn lightly toasted and smell nutty.
Add the minced garlic to the rice and cook for 30 seconds until fragrant, being careful not to burn it.
Pour in a ladle of warm broth and stir continuously until the liquid is mostly absorbed, about 2-3 minutes. Repeat this process, adding broth one ladle at a time, allowing each addition to be absorbed before adding the next, maintaining a gentle simmer.
About 10 minutes into cooking, stir in the chopped asparagus. Continue adding broth and stirring, watching the asparagus turn bright green and tender, which should take another 5-7 minutes.
Once the rice is tender but still has a slight bite (al dente), remove the pan from heat. Stir in the butter, grated Parmesan, and lemon zest and juice, seasoning with salt and pepper to taste.
Let the risotto sit for 2 minutes to thicken slightly, then give it a final stir and taste for seasoning adjustment.
Serve immediately in warm bowls, garnished with reserved asparagus tips or extra Parmesan for a beautiful presentation.
