Butternut Squash & Caramelized Onion Casserole with Chestnuts

1. Preheat the oven

Preheat your oven to 375°F. This will ensure it's ready to go once you've prepped your ingredients.

2. Caramelize the onions

Place the sliced onions into a 9x13-inch baking dish and toss them with 1/3 cup of olive oil. Spread them out evenly in the dish. Bake for about 30 minutes, stirring occasionally with a wooden spatula. The slow roasting will caramelize the onions, bringing out their natural sweetness and depth of flavor. You'll know they're ready when they are browned and sizzling.

3. Prepare chestnuts

While the onions are roasting, prepare your chestnuts. If you're using fresh chestnuts, you'll need to peel them. If you're using pre-peeled chestnuts, either thaw them (if frozen) or drain them (if jarred). This ensures the chestnuts are ready to be incorporated seamlessly into the casserole.

4. Combine ingredients

Once the onions are caramelized, add the chestnuts, cubed butternut squash, white beans, dried thyme, ground coriander, freshly grated nutmeg, salt, freshly cracked pepper, and vegetable broth to the baking dish. Stir everything together to combine well. Cover the dish tightly with aluminum foil and bake for 35 to 45 minutes. Covering the dish traps steam, which helps to tenderize the squash and chestnuts, creating a harmonious blend of flavors.

5. Prepare crumb topping

While the casserole is baking, prepare the crumb topping. In a bowl, toss together the dry white bread crumbs, 2 tablespoons of olive oil, dried rubbed sage, a pinch of ground cayenne, 1/2 teaspoon of salt, and some freshly cracked pepper. This mixture will add a delightful crunchy texture to the dish.

6. Add topping and bake

After the casserole has baked for 35 to 45 minutes, remove the foil and sprinkle the crumb mixture evenly over the top. Return the dish to the oven and bake for an additional 15 minutes. The topping should be lightly browned, adding a perfect crunch to the tender, flavorful casserole beneath.