01 - Heat olive oil in a large heavy-bottomed saucepan or Dutch oven over medium heat. Season cubed chicken generously with salt and pepper. Add to pan in a single layer and cook without disturbing for 2-3 minutes until golden-brown. Turn and cook 2-3 minutes longer until cooked through. Transfer chicken to a plate and tent with foil.
02 - Reduce heat to medium-low. Add 1 tablespoon butter to the same pan. When butter foams, add diced onion and cook 3-4 minutes until translucent and softened. Stir in minced garlic and cook 60 seconds until fragrant, being careful not to brown.
03 - Add Arborio rice to the pan. Cook, stirring constantly with a wooden spoon, for 2-3 minutes until rice grains are opaque around edges and give off a nutty aroma.
04 - Pour in white wine while stirring continuously. Cook 1-2 minutes until wine is completely absorbed and the sharp alcohol smell has evaporated.
05 - Add hot broth one ladleful at a time (approximately 1/2 cup per addition). Stir frequently, allowing rice to absorb most of the liquid before adding more. Continue this process for approximately 15 minutes until rice has swollen and begun to soften.
06 - Stir in asparagus pieces. Continue adding broth ladle by ladle, stirring often, for another 10-12 minutes. Rice is done when grains are tender but still firm to the bite (al dente) and texture is creamy and flowing. You may not need all the broth.
07 - Remove from heat. Add cooked chicken, remaining 2 tablespoons butter, Parmesan cheese, and lemon zest. Stir vigorously to emulsify. Taste and adjust seasoning with salt and pepper. Cover and let rest 2 minutes to allow flavors to meld. Serve in warmed bowls, topped with additional Parmesan and parsley if desired.