Pat the chicken dry with paper towels then drizzle with a few teaspoons of oil. Season generously with salt and pepper on both sides.
Heat a large, deep skillet or pan (you could use a pot too) over medium-high heat then add the chicken. Sear on both sides until deeply golden brown and cooked through - approximately 3-4 minutes per side.
Remove from the pan and set aside.
In the same pan over medium heat, add another tablespoon of oil then add the onion and allow to sauté for a few minutes until softened. Add the garlic, mushrooms and thyme and sauté for 5 minutes.
Add the rice and stir to combine with the mushrooms then pour in the wine.
Allow to reduce for 1-2 minutes then start adding the stock in batches, stirring and allow the rice to absorb the liquid before adding more. This will take 15-20 minutes over medium-low heat.
Once the rice is cooked and has reached a creamy consistency, stir in the cubed butter, cream, truffle oil and lemon juice. Stir in the Parmesan cheese.
Season with salt and pepper.
Slice the chicken then add to the top of the risotto, allow to warm for a minute or two then serve.