01 - Heat olive oil in a large heavy saucepan over medium heat. Season diced chicken generously with salt and pepper. Cook until browned on all sides and cooked through, approximately 5–6 minutes. Transfer chicken to a plate and set aside.
02 - In the same pan, add 1 tablespoon butter. Sauté chopped onion until translucent and fragrant, about 3 minutes. Add minced garlic and stir constantly for 1 minute until aromatic but not browned.
03 - Add Arborio rice to the pan. Cook, stirring continuously, for 2 minutes until rice grains are translucent around edges and lightly toasted. This creates the al dente texture essential to proper risotto.
04 - Pour in white wine while stirring. Continue stirring until wine is completely absorbed and the alcohol has evaporated, about 1–2 minutes.
05 - Add warm chicken stock one ladleful at a time (approximately 1/2 cup per addition). Stir frequently, allowing each addition to be fully absorbed before adding more. Continue this process for about 15 minutes until rice begins to soften.
06 - Stir in asparagus pieces when rice is partially cooked. Continue adding stock ladle by ladle, maintaining gentle stirring, for another 10 minutes. The risotto is done when rice is creamy with a slight bite at the center and asparagus is tender-crisp.
07 - Return cooked chicken to the pan. Stir in remaining 2 tablespoons butter, Parmesan cheese, and lemon zest until butter melts and mixture becomes glossy. Adjust seasoning with additional salt and pepper. Remove from heat, cover, and rest for 2 minutes to allow flavors to meld.
08 - Spoon risotto into warmed bowls. Garnish with chopped parsley and additional grated Parmesan if desired. Serve immediately while risotto is at its optimal creamy consistency.