Season & Sear: Pat chicken dry. Season all over with salt and black pepper. Heat olive oil in a Dutch oven over medium-high. Sear chicken, skin-side down first, 5–6 minutes per side until deep golden. Transfer to a plate.
Sauté Aromatics: In the same pot (leave the flavorful brown bits), add onion and cook 3–4 minutes until translucent. Stir in garlic for 30 seconds until fragrant. Add sliced bell peppers and mushrooms; sauté 5–6 minutes until softened and lightly browned.
Build the Sauce: Pour in crushed tomatoes, chicken broth, and white wine. Scrape the bottom to deglaze. Stir in oregano, thyme, bay leaf, and red pepper flakes. Bring to a gentle simmer.
Simmer Chicken: Return chicken and any juices to the pot, nestling pieces into the sauce. Cover and simmer on low for 30–35 minutes, until chicken is tender and reaches 165°F (74°C). For a thicker sauce, uncover for the last 10 minutes.
Finish & Rest: Remove bay leaf. Taste and adjust salt and pepper (add a pinch of sugar if the tomatoes taste sharp). Let rest 5 minutes. Garnish with chopped parsley or basil.
Serve: Spoon over pasta, creamy polenta, rice, or with crusty bread. Optional: finish with grated Parmesan.