Warm the stock in a microwave or in a small pot on the stove. Turn heat to low and keep warm. Preheat oven to 425ºF.
Start the Risotto:
Heat the olive oil in a pot over medium heat. Add the onion and cook for 2-3 minutes until it just begins to soften. Add the mushrooms and cook for 12-13 minutes, stirring occasionally, until the mushrooms are golden brown.
They should release all their liquid and the liquid should evaporate from the pan. Add the garlic and cook for 45 seconds until fragrant. Season with salt and pepper. Leave the mushrooms in the pot.
Cook the Chicken:
As the mushrooms are cooking, start the chicken. Pat the chicken dry and season all over with salt and pepper. Heat neutral cooking oil in a skillet over medium-high heat.
Once hot, add the chicken, skin-side down, and cook without moving for 5 minutes until the skin is very crispy and browned. Flip the chicken and transfer to the oven for 20-25 minutes until completely cooked through. Turn off the oven and keep the chicken in the oven as you finish the risotto to keep it warm.
Cook the Rice:
Melt the butter into the pot of mushrooms and onions. Once melted, add the rice. Cook, stirring regularly, for 2-3 minutes until the rice is coated with butter and begins to turn golden brown.
Add the aji amarillo paste and toss to coat.
Pour in the white wine and scrape up any browned bits stuck to the bottom of the pot. Bring to a boil and then reduce heat to low.
Once the wine has been absorbed, add 1 cup of the stock and stir regularly until absorbed. Continue on, adding a cup of stock, stirring until absorbed and then adding more stock until all of the stock has been incorporated, about 20-25 minutes total. Taste and season to your preferences. Turn off the heat and allow the risotto to rest for 5 minutes before serving.
To Serve:
Divide the risotto between shallow bowls and serve with a chicken thigh on top. Garnish with parsley, if desired. Enjoy!