01 - In a medium saucepan, bring the vegetable stock to a gentle simmer over low heat. Keep warm throughout the cooking process.
02 - In a large, heavy-bottomed pan, heat the olive oil and 1 tablespoon butter over medium heat. Add the chopped onion and cook until translucent, about 3 minutes. Stir in the minced garlic and cook for 1 minute until fragrant.
03 - Add the Arborio rice to the pan and stir to coat thoroughly with the oil and butter mixture. Cook for 1-2 minutes, stirring constantly, until the grains are lightly toasted and have a opaque edge.
04 - Pour in the white wine and cook, stirring continuously, until nearly completely absorbed by the rice.
05 - Add a ladleful of hot stock to the rice, stirring frequently. Once the liquid is mostly absorbed, add another ladleful. Continue this process, stirring and adding more stock as it absorbs, for about 15 minutes.
06 - Stir in the asparagus pieces and continue cooking, adding stock as needed, for another 10 minutes. Maintain gentle stirring to release starches for creaminess.
07 - Add the peas and cook for a final 5 minutes, or until the rice is creamy and just tender (al dente), and the vegetables are bright and cooked through.
08 - Remove from heat. Stir in the remaining butter, Parmesan cheese, lemon zest, parsley, and heavy cream if using. Season generously with salt and pepper to taste.
09 - Let the risotto rest, covered, for 2 minutes to allow flavors to meld. Serve hot, garnished with extra parsley and Parmesan cheese.