Preheat the oven to 400°F (200°C).
Pat the chicken dry with paper towels. Rub it with olive oil, thyme, rosemary, paprika, garlic powder, salt, and black pepper.
Add the sliced onions and sprinkle them with salt. Cook slowly for approximately 25–35 minutes, stirring every few minutes.
Once deeply golden, stir in balsamic vinegar and cook for another 1–2 minutes. Remove from the skillet and set aside.
Roast for approximately 25–35 minutes, depending on the thickness and cut of the chicken.
The safest way to determine doneness is with an instant-read thermometer. Chicken should reach an internal temperature of 165°F (74°C).
While the chicken is roasting, place the chicken broth in a saucepan and keep it warm over low heat.
Heat olive oil and 1 tablespoon butter in a large heavy-bottomed skillet over medium heat.
Pour in the white wine, if using. Stir until most of the liquid has been absorbed.
Add approximately ½ cup of warm broth to the rice. Stir frequently until the liquid is mostly absorbed.
Continue for approximately 18–25 minutes, until the rice is creamy but still has a slight bite in the center.
Remove the skillet from the heat.
The risotto should be creamy and slightly loose rather than stiff.
Place sliced roasted chicken on top or alongside the risotto. Add a generous spoonful of caramelized onions.
Serve immediately.