1 tablespoon cornstarch, dissolved in 1 teaspoon cold water
1 ½ teaspoons fish sauce
1 teaspoon rice vinegar
½ teaspoon chili flakes
3 tablespoons olive oil
1 medium onion, diced
3 cloves garlic, minced
½ small fresh red chili, thinly sliced
Kosher salt and freshly ground black pepper to taste
Parsley, for garnish
Zest one of the oranges and reserve the zest. Halve both oranges. Juice three of the halves to yield about ½ cup juice (drink any extra), then slice the other half into four rounds and reserve. Combine the ½ cup orange juice with reserved orange zest, broth, maple syrup, cornstarch, fish sauce, rice vinegar, and chili flakes, then reserve.
Season the chicken generously with salt and pepper. Heat the oil over medium-high heat in a large nonstick skillet. Brown the chicken until golden (but not cooked through), 2–3 minutes per side. Remove to a plate and cover with foil to keep warm.
Add the remaining tablespoon oil to the skillet, reduce the heat to medium, add the onions and cook, stirring, until tender and translucent, 8–9 minutes. Add the garlic and cook, stirring, 1 more minute.
Set an oven rack 6–8 inches from the heating element and preheat the broiler to high broil. Add the reserved orange juice mixture to the onions and garlic, raise the heat to medium-high, bring to a boil, let boil and thicken for 1–2 minutes, then reduce the heat to medium, return the chicken to the skillet, spoon some of the sauce over the chicken, and arrange an orange slice over each piece.
Transfer the pan to the preheated oven and broil until the oranges begin to soften and blacken slightly around the edges, 3–4 minutes. Remove from the oven and garnish with chilies and parsley. Serve with steamed white rice or bacon & broccoli garlic fried rice.