01 - Heat olive oil in a large heavy saucepan over medium heat. Season diced chicken with salt and pepper, add to pan, and cook until browned and cooked through, about 5 to 6 minutes. Remove chicken and set aside on a plate.
02 - In the same pan, add 1 tablespoon butter. Sauté chopped onion until translucent and soft, about 3 minutes. Stir in minced garlic and cook for 1 minute until fragrant.
03 - Add Arborio rice to the pan and cook, stirring constantly, for 2 minutes until grains are lightly toasted and edges become translucent.
04 - Pour in white wine and stir continuously until completely absorbed by the rice, about 1 to 2 minutes.
05 - Add hot chicken stock one ladleful at a time, stirring frequently. Allow each addition to be fully absorbed before adding the next. Continue this process for about 15 minutes.
06 - Stir in asparagus pieces and continue adding stock gradually, cooking for another 10 minutes. Rice should be creamy and al dente with a slight bite, and asparagus should be just tender.
07 - Return cooked chicken to the pan. Stir in remaining butter, Parmesan cheese, and lemon zest until butter melts and cheese incorporates. Adjust seasoning with additional salt and pepper as needed.
08 - Remove from heat, cover, and let rest for 2 minutes to allow flavors to meld. Garnish with chopped parsley and additional Parmesan if desired. Serve immediately while creamy.