Heat 2 tablespoons olive oil in a skillet over medium-high heat. Sear bone-in chicken thighs skin-side down for 3-4 minutes until golden, then flip and sear another 3 minutes. Transfer the chicken to a plate.
2 tbsp olive oil, 6 pieces bone-in chicken thighs
Pour ½ cup red wine into the hot skillet and scrape up the browned bits with a wooden spoon for 1-2 minutes. Set the deglazed wine aside.
0.5 cup red wine
Place sliced onions and bell peppers in the bottom of a 4-6 quart slow cooker. Sprinkle minced garlic and dried oregano over the vegetables. Arrange seared chicken thighs over the top. Pour crushed tomatoes and the deglazed wine over everything.
1 large onion, 2 medium bell peppers, 4 cloves garlic, 1 tbsp dried oregano, 6 pieces bone-in chicken thighs, 28 oz crushed tomatoes, 0.5 cup red wine
Cover and cook on low for 5 hours. If using mushrooms or olives, stir them in during the last hour of cooking. Remove the lid during the last 30 minutes to thicken the sauce. Check that the chicken reaches 165°F internal temperature using an instant-read thermometer.
8 oz mushrooms, 0.5 cup black olives, 6 pieces bone-in chicken thighs
Taste the sauce and adjust salt if needed. Let the chicken rest for 5 minutes before serving. Serve over polenta, mashed potatoes, pasta, or with crusty bread to soak up the sauce.
