01 - In a medium saucepan, bring the vegetable stock to a gentle simmer over low heat. Maintain at a simmer 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, approximately 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 to 2 minutes until the rice grains are lightly toasted and have a translucent edge.
04 - Pour in the dry white wine and cook, stirring continuously, until nearly completely absorbed by the rice.
05 - Add one ladleful of hot stock to the rice, stirring frequently. Once the liquid is nearly absorbed, add another ladleful. Continue this process of stirring and adding stock as it is absorbed for approximately 15 minutes.
06 - Stir in the asparagus pieces and continue cooking, maintaining the rhythm of adding stock as needed, for another 10 minutes until the asparagus begins to tenderize.
07 - Add the green peas and cook for a final 5 minutes, or until the rice is creamy and just tender with a slight bite (al dente), and the vegetables are bright green and cooked through.
08 - Remove the pan from heat. Stir in the remaining butter, grated Parmesan, lemon zest, chopped parsley, and heavy cream if using. Season generously with salt and freshly ground black pepper to taste.
09 - Let the risotto rest, covered, for 2 minutes to allow flavors to meld. Serve hot, garnished with additional chopped parsley and freshly grated Parmesan cheese.