01 - Heat 2 tablespoons butter in a large heavy-bottomed saucepan over medium heat. Add onion and cook 3–4 minutes until translucent. Stir in garlic and cook 1 minute more.
02 - Add Arborio rice and cook, stirring constantly, for 2 minutes until grains are well coated and slightly translucent at edges.
03 - Pour in white wine and simmer, stirring, until almost fully absorbed.
04 - Add warm vegetable broth one ladleful at time, stirring gently and allowing each addition to absorb before adding next. Continue for about 15 minutes.
05 - Stir in asparagus 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, Parmesan cheese, and heavy cream if using. Season with salt, pepper, and lemon zest if desired.
07 - Cover and let rest 2 minutes. Serve immediately, garnished with extra Parmesan.