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 more 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 completely 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 the next. Continue this process for approximately 15 minutes.
05 - Stir in asparagus pieces and peas. Continue adding broth and stirring until rice is creamy and al dente, and vegetables are tender, about 8–10 minutes more.
06 - Remove from heat. Stir in remaining butter, grated Parmesan cheese, and heavy cream if using. Season generously with salt, pepper, and lemon zest if desired.
07 - Cover and let rest for 2 minutes to allow flavors to meld. Serve immediately, garnished with additional Parmesan cheese.