Pour the vegetable broth into a saucepan and heat gently over low heat, keeping it simmering.
Heat a wide pan over medium and add the olive oil. Once shimmering, stir in the finely chopped onion, cooking until translucent and fragrant, about 3 minutes.
Add the Arborio rice to the pan and stir constantly for about 2 minutes until the edges turn slightly translucent and the rice begins to crackle, releasing a nutty aroma.
Pour in a ladleful of warm broth and stir gently. Wait until the liquid is mostly absorbed before adding another ladleful. Continue this process, stirring constantly, for about 15 minutes until the rice is creamy but still has a slight bite.
When the rice is halfway cooked, stir in the green peas. Let them cook for about 5 minutes until bright green and tender, infusing the risotto with their sweet aroma.
Continue adding broth until the rice reaches the desired creamy and al dente consistency, approximately 20 minutes total. Turn off the heat.
Stir in the grated parmesan, butter, and lemon zest if using, until melted and glossy. Adjust seasoning with salt and pepper as needed.
Cover the pan loosely and let the risotto rest for 2 minutes, allowing flavors to meld and the texture to become even creamier.
Gently stir again before serving, then dish out the vibrant, velvety risotto with bright green peas peeking through. Enjoy immediately!
