Serves: 6-8, depending on the appetite
- Extra-virgin olive oil
- 1 large onion, diced into 1/2-inch pieces
- 2 celery stalks, diced into 1/2-inch pieces
- 1 large carrot, peeled and diced into 1/2-inch pieces
- Kosher salt
- fresh ground pepper
- 2 cloves garlic, smashed and finely chopped
- 2 cups butternut squash, peeled and diced into 1/2-inch pieces
- 1 tsp nutmeg
- 1 cup frozen peas
- 6 sage leaves, finely chopped (or 2 tsp dried sage)
- 4 tablespoons butter
- 4 tablespoons all-purpose flour
- 3 medium potatoes, peeled and sliced into 1″ rounds
- 1/4 cup grated Gruyère cheese
- 2 Tbsp. butter
- 2/3 cup buttermilk
In a medium saucepan, add potatoes to water and bring to a rolling boil. Boil until potatoes are soft when poked with a fork (8 minutes). Drain and add in buttermilk. Mash until a smooth consistency, adding in butter and cheese. Place to the side while you make the filling.
For the filling, coat the bottom of a stock pot lightly with olive oil put over medium heat. Add the onions, celery and the carrots and sprinkle with salt, to taste. Saute the vegetables for 7 to 8 minutes. Add the garlic and sweat for another 2 to 3 minutes. Season with salt, then add the chicken and the chicken stock. If the stock doesn’t cover the chicken, add water until it does. Bring the stock to a boil, over high heat, then reduce the heat and simmer for 30 minutes.
Preheat the oven to 375 degrees.
While the chicken is simmering, add the butternut squash to a large bowl, drizzle with some olive oil, adding salt to taste and 1/4 tsp of the nutmeg. Toss to coat the squash with the oil and transfer to a foil-lined baking sheet. Roast until the squash is cooked but still has some texture, about 15 minutes. Remove from the oven and reserve.
Remove the chicken and vegetables from the stock and put into a large bowl. Reserve the stock by pouring in into another bowl. When the cool enough to handle, remove the bones from the chicken and stir into the vegetables. Add the roasted squash to the chicken and vegetables. Stir to combine and season with salt, if needed. In a small saucepan, add the peas into 1 cup water and boil bring to boil. Immediately drain and add peas to chicken and vegetables. Stir in sage.
For the gravy, melt the butter in the stockpot used to cook the chicken and vegetables over low heat. Add the flour and whisk to combine with melted butter. Cook while whisking frequently until the mixture is the consistency of wet sand and is starting to turn a little beige, about 6 to 7 minutes. Gradually whisk in the reserved chicken stock. Taste and adjust seasoning, if needed, adding in pepper and the remaining nutmeg. When the stock is combined into the roux, bring to a boil, then reduce the heat and simmer until it has a gravy-like consistency, about 25 minutes. If the gravy reduces too much and becomes too thick, whisk in a little more chicken stock or water.
Add the chicken mixture into a 2-quart casserole dish. Ladle the “gravy” over the chicken mixture until the dish is 3/4 filled. Spoon the mashed potatoes over the top, gently spreading it out to fully cover the filling. Place dish on a foil-lined baking sheet.
Bake in the preheated oven until the crust begins to get a golden brown color and the inside is hot and bubbly, about 30 to 35 minutes. Remove from the oven and serve hot.