Heat the olive oil in your heavy-bottomed pan over medium heat until it shimmers, and add the finely chopped shallot. Cook, stirring frequently, until translucent and fragrant, about 3 minutes.
Add the sliced mushrooms to the pan and cook until they release their moisture and turn golden brown, about 5-7 minutes. Season lightly with salt and pepper, then transfer to a plate and set aside.
In the same pan, add the Arborio rice and stir constantly for about 2 minutes until the edges become slightly translucent and the rice smells toasty. This step builds flavor and prevents sticking.
Pour in the white wine and stir until it mostly evaporates, about 2 minutes. This adds a bright acidity and depth to the dish.
Begin adding the warm vegetable broth one ladleful at a time, stirring gently after each addition. Wait until the liquid is mostly absorbed before adding the next ladle. Continue this process, stirring frequently, for about 15-20 minutes, until the rice is tender but still slightly chewy.
Once the rice reaches the desired consistency, stir in the cooked mushrooms, butter, and freshly grated Parmesan cheese. Adjust seasoning with salt and pepper to taste, then remove from heat.
Let the risotto rest for a minute or two to settle and develop a velvety, glossy appearance. Serve immediately, garnished with extra Parmesan if desired.
