Vegetarian Butternut Squash Casserole with Apples

Butternut squash and apple crumble with mushrooms in a baking dish.

4 from 3 votes

Vegetarian Butternut Squash Casserole with Apples

Butternut squash casserole with apples, caramelized mushrooms, and shallots, all topped with a buttery crumble topping mixed with a little fig jam.

Prep Time20

Cook Time45

Total Time1 5

Course: Vegetable Side

Cuisine: Any

Keyword: butternut squash casserole

Servings: Sides

Calories: 310.8kcal

Author: Susan Pridmore

Equipment

Chef's knife
Vegetable peeler
8" X 8" Casserole dish 9-inch deep dish pie plate

Ingredients

Butternut Squash-Apple Filling

4 cups peeled and diced butternut squash diced into ¾" pieces
1 tablespoon avocado oil or other high heat cooking oil
2 tablespoons unsalted butter plus more for buttering the pie dish
1 cup thinly sliced mushrooms or coarsely chopped
1 cup finely chopped shallots 2 - 3 large shallots
1 teaspoon kosher salt divided (or ½ teaspoon table salt)
½ teaspoon Better Than Bouillon Vegetable Bouillon Paste, divided (or vegetable broth or water)
1 teaspoon balsamic vinegar
2 teaspoons chopped fresh thyme
3 cups thinly sliced apples cored but unpeeled (see Ingredient Notes)
3 tablespoons dried cranberries

Crumble Topping

⅓ cup all-purpose flour
⅓ cup oats
1 tablespoon brown sugar
½ teaspoon kosher salt or ¼ teaspoon table salt
4 tablespoons unsalted butter, room temperature
1 tablespoon fig jam or just add another tablespoon brown sugar

Instructions

Preheat the oven to 375˚F (190˚C) and generously butter a 9" pie plate or an 8" X 8" oven-safe casserole dish.
Prep the squash. Peel and cube the butternut squash. (See the How to Prep Butternut Squash section in the post if you need tips on the best way to do this.)
Place the diced butternut squash in a large mixing bowl and toss with only enough avocado oil to completely coat the squash.
Cook the butternut squash.
Instructions for air frying butternut squash:
Preheat the air fryer to 375˚F (190˚C). Arrange the butternut squash in the air fryer basket in an even layer. The more spread out the squash is, the better it will roast. Air fry for 12 minutes or until lightly caramelized, shaking the basket halfway through cooking. Set aside.
Instructions for roasting butternut squash in the oven:
Preheat the oven to 400˚F. (The oven is already preheating to 375˚F to bake the casserole, so if you roast the squash in the oven, lower it back to 375˚F after the butternut squash roasts.) Line a rimmed baking sheet with parchment paper, and spread the diced butternut squash across it. Roast for 15 - 20 minutes until tender, depending on the size of the diced squash. Set aside.
Sauté the mushrooms. Melt the butter in a large skillet over medium heat. Add the sliced mushrooms, shallots, and ½ teaspoon kosher salt (¼ teaspoon table salt).
Cook until the shallots and mushrooms soften and melt into the butter.
Once they reach this stage, continue to cook them, but only move the mushrooms and shallots around the pan every 5 minutes. This allows them to caramelize. A brown fond will develop on the bottom of the pan as it becomes dry.
Stir in ¼ cup water and ¼ teaspoon Better Than Bouillon paste or ¼ cup vegetable broth and scrape up the bits of fond from the bottom of the pan. Stir in the balsamic vinegar and fresh thyme.
Combine. Add the roasted butternut squash to the pan along with the apples and dried cranberries. Toss to mix in the pan so the the caramelized mushrooms coat everything well.
Bake. Transfer the squash filling into the prepared pie plate or casserole dish, and add the final ¼ teaspoon of Better Than Bouillon paste diluted in ¼ cup water (or ¼ cup vegetable broth).
Cover with foil and bake for 10 minutes.
Crumble.Whisk together the flour, oats, brown sugar, and salt in a small bowl.
Slice the butter into thin pieces and add to the mixture. Pinch the butter in the mixture using your fingers or a pastry blender until the crumble is coarse. Some chunks of butter should be the size of peas.
Gently stir in the fig jam.
Finish. Remove the butternut squash casserole from the oven, and uncover it. Scatter the crumble over the top of the casserole and return it to the oven for another 15 minutes, or until the topping is golden brown.
Serve warm.

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