Warm the broth: In a saucepan, bring the chicken broth to a bare simmer and keep it warm over low heat. Warm broth helps the rice cook evenly.
Sear the chicken: In a wide, heavy pot, heat 1 tablespoon olive oil over medium-high.
Season the chicken with salt and pepper. Sear until lightly browned and just cooked through, 4–6 minutes. Transfer to a plate.
Sauté the mushrooms: Add the remaining 1 tablespoon oil and the butter to the pot.
Add mushrooms with a pinch of salt. Cook, stirring occasionally, until they release moisture and turn golden, 5–7 minutes.
Build the flavor base: Add onion and cook until softened, 3–4 minutes. Stir in garlic and thyme for 30 seconds until fragrant.
Toast the rice: Stir in the Arborio rice.
Cook 1–2 minutes, coating the grains in the fat until the edges look slightly translucent. This deepens flavor and helps the rice hold texture.
Deglaze with wine: Pour in the white wine and stir, scraping up any browned bits. Cook until most of the wine evaporates, about 2 minutes.
If not using wine, add a ladle of broth instead.
Add broth gradually: Add 1 ladle (about 1/2 cup) of warm broth. Stir often, keeping the rice at a gentle simmer. When the liquid is mostly absorbed, add another ladle.
Repeat, stirring and adding broth, 18–22 minutes total.
Monitor doneness: Taste as you go. The risotto is ready when the rice is al dente—tender with a slight bite—and the texture is creamy and loose, like thick porridge.
Finish the risotto: Stir the chicken back in to heat through. Off the heat, add Parmesan and a small knob of butter if you like.
Adjust salt and pepper. Add a little more broth if it’s too thick; risotto should gently flow on the spoon.
Brighten and serve: Stir in parsley or chives and a touch of lemon zest or juice for brightness. Serve immediately with extra Parmesan.