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Autumnal Chicken and Onion Casserole

This casserole combines savory roasted chicken skin, caramelized onions, and fresh sage baked together until golden and bubbling, creating a comforting dish with rich aromas and satisfying textures. Topped with fluffy mashed potatoes and crispy edges, it offers a hearty, rustic meal that captures the essence of fall flavors.
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Prep Time 20 minutes
Cook Time 45 minutes
Total Time 1 hour 5 minutes
Servings: 4
Course: Main Course
Cuisine: Comfort Food
Calories: 550
Ingredients Equipment Method Notes

Ingredients
  

  • 4 pieces bone-in chicken thighs skin on for extra flavor
  • 2 large onions sliced
  • 2 tablespoons olive oil for roasting and sautéing
  • 1 teaspoon dried sage or fresh sage leaves chopped
  • salt and pepper to taste
  • 4 medium potatoes peeled and cut into chunks
  • 2 tablespoons butter for mashed potatoes
  • ½ cup milk milk or cream

Equipment

  • Chef's knife
  • Cutting board
  • Skillet or Pan
  • Baking dish
  • Pot for Mashed Potatoes
  • Masher or Fork

Method
 

  1. Preheat your oven to 400°F (200°C).
  2. Rub the chicken thighs with salt, pepper, and half of the sage, then set aside.
    4 pieces bone-in chicken thighs, 1 teaspoon dried sage, salt and pepper to taste
  3. Heat one tablespoon of olive oil in a skillet over medium-high heat until shimmering.
    2 tablespoons olive oil
  4. Place the chicken thighs skin-side down and sear for about 5-7 minutes until the skin is crispy and golden.
    4 pieces bone-in chicken thighs
  5. Flip the chicken and cook for another 4-5 minutes, then transfer to a plate and set aside.
    4 pieces bone-in chicken thighs
  6. Add the sliced onions to the skillet and sauté in the remaining oil, stirring occasionally, until they are golden brown and caramelized—about 15 minutes.
    2 large onions
  7. Stir in the remaining sage and season with salt and pepper, then return the chicken to the skillet, placing it skin-side up among the onions.
    2 large onions, 1 teaspoon dried sage, salt and pepper to taste, 4 pieces bone-in chicken thighs
  8. Transfer the skillet or transfer everything to a baking dish if your skillet isn't ovenproof, then bake in the preheated oven for 25-30 minutes, until the chicken is cooked through and fragrant.
  9. While the casserole bakes, cook the potatoes in boiling salted water until tender, about 15 minutes.
    4 medium potatoes
  10. Drain the potatoes and mash with butter and milk until smooth and creamy, adjusting with more milk if needed.
    2 tablespoons butter, ½ cup milk milk
  11. Spread the mashed potatoes evenly over the cooked chicken and onion mixture, smoothing the surface with a spatula.
  12. Place the dish back in the oven for an additional 10-15 minutes, until the top is lightly golden and the casserole is bubbling around the edges.
  13. Remove from the oven, let rest for a few minutes, then serve hot, enjoying the rich aroma and inviting layers of flavor.

Notes

Feel free to add leftover roasted vegetables or a splash of apple cider for extra fall flavor.