Heat olive oil in a large skillet over medium heat.
Add chopped shallots and minced garlic, sauté for 2 minutes until fragrant.
Add sliced chestnut mushrooms to the skillet, cook until they release their juices and become tender.
Stir in Arborio rice and continue cooking, stirring constantly until the rice grains are coated with oil and start to turn translucent.
Gradually pour in about 3/4 of the vegetable broth, stirring continuously.
Allow the rice to absorb the broth while stirring frequently.
As the rice absorbs the broth and begins to dry out, add more broth in small increments, stirring frequently, until the rice is cooked through and creamy, about 20 minutes in total.
Add frozen peas during the last 7 minutes of cooking time, allowing them to cook until tender.
Season the risotto with salt, pepper, and chopped parsley, adjusting the seasoning to taste.
Serve hot, sprinkled with grated Parmesan cheese at the table.