In a large Dutch oven or saucepan, heat 1 tablespoon of the butter over medium heat. When foaming subsides, add asparagus and ¼ cup water. Cook, stirring occasionally, until water has evaporated and asparagus is crisp-tender, about 4-6 minutes. Add the peas and continue to cook for 1 minute. Transfer vegetables to a plate and set aside.
In the same Dutch oven or saucepan, heat 3 tablespoons of the butter over medium heat. When the foaming subsides, add the leeks, shallots, garlic, salt, and pepper. Cook, stirring occasionally, until leeks and shallots are softened, about 4-5 minutes. Add the rice and cook, stirring frequently, until grains are translucent around the edges, about 3 minutes. Add the wine and cook, stirring frequently until fully absorbed, about 2-3 minutes.
When the wine is fully absorbed, add 3 cups of the hot broth. Simmer, stirring every 3-4 minutes, until the liquid is absorbed and the bottom of the pan is almost dry, about 12 minutes.
Stir in ½ cup of the hot broth and cook, stirring occasionally, until absorbed, about 3 minutes; repeat with additional broth 3 or 4 times until rice is al dente. Off heat, stir in remaining tablespoon of butter, Parmesan, and lemon juice; gently fold in asparagus and peas. If desired, add up to ¼ cup hot broth to loosen texture of risotto. Serve immediately, sprinkling each serving with the herb garnish and passing additional Parmesan separately. Enjoy!