01 - Heat olive oil in a large, heavy saucepan or Dutch oven over medium heat. Season diced chicken generously with salt and pepper. Add to the pan and cook, stirring occasionally, until browned on all sides and cooked through, about 5 to 6 minutes. Remove chicken with a slotted spoon and set aside on a plate.
02 - In the same pan, add 1 tablespoon butter. Add chopped onion and cook, stirring occasionally, until translucent and softened, about 3 minutes. Stir in minced garlic and cook for 1 minute until fragrant, being careful not to brown the garlic.
03 - Add Arborio rice to the pan and cook, stirring constantly, for 2 minutes until the grains are lightly toasted and the edges become translucent. This toasting step helps the rice maintain its texture during cooking.
04 - Pour in the white wine and stir continuously until completely absorbed by the rice, about 1 to 2 minutes. The wine adds acidity and depth of flavor to the finished dish.
05 - Begin adding the warm chicken stock one ladleful at a time (about 1/2 cup per addition), stirring frequently. Allow each addition to be almost completely absorbed before adding the next. Continue this process for about 15 minutes, maintaining a gentle simmer throughout.
06 - Stir in the asparagus pieces and continue adding stock ladle by ladle, cooking for another 10 to 12 minutes. The rice is done when it's creamy but still retains a slight bite in the center (al dente) and the asparagus is tender-crisp. You may not need all the stock.
07 - Return the cooked chicken to the pan along with any accumulated juices. Stir in the remaining 2 tablespoons butter, Parmesan cheese, and lemon zest. Taste and adjust seasoning with additional salt and pepper as needed. The risotto should be creamy and flow slowly when you tilt the pan.
08 - Remove from heat, cover, and let rest for 2 minutes to allow the flavors to meld. Transfer to serving bowls and garnish with chopped parsley and additional Parmesan cheese. Serve immediately while hot and creamy.