01 - Heat 2 tablespoons butter in a large heavy-bottomed saucepan over medium heat. Add chopped onion and cook 3–4 minutes until translucent. Stir in minced garlic and cook 1 minute until fragrant.
02 - Add Arborio rice to the pan, stirring constantly for 2 minutes until grains are well coated with butter and slightly translucent at the edges.
03 - Pour in white wine and simmer, stirring continuously, until almost fully absorbed by the rice.
04 - Add warm vegetable broth one ladleful at a time, stirring gently and allowing each addition to absorb completely before adding more. Continue this process for approximately 15 minutes.
05 - Stir in asparagus pieces and peas. Continue adding broth gradually and stirring until rice is creamy and al dente, and vegetables are tender, about 8–10 minutes longer.
06 - Remove from heat. Stir in remaining 1 tablespoon butter, grated Parmesan, and heavy cream if using. Season with salt, pepper, and lemon zest as desired.
07 - Cover and let rest 2 minutes to allow flavors to meld. Serve immediately, garnished with additional Parmesan cheese if desired.