Butternut Squash Casserole is fluffy and delicious with homemade butternut squash purée and a hearty pecan streusel topping. It's a great holiday side dish and it may be made entirely in advance!
Preheat the oven to 375 degrees F. Line a rimmed baking sheet with foil. Rub the butternut squash halves with the oil and place cut side down on the baking sheet. Roast 35-45 minutes or until fork tender.
When cool enough to handle, scoop out the butternut squash flesh and purée in a food processor until smooth. You'll end up with roughly 4 - 4 1/2 cups of purée.
Transfer the purée to a fine mesh sieve lined with cheesecloth placed over a bowl. Cover loosely with plastic wrap and let stand in the refrigerator overnight to allow liquid to drain from the purée.
Preheat the oven 350 degrees F when you're ready to bake the casserole, and spray an 8x8" baking dish with cooking spray.
Beat the butternut squash, eggs, maple syrup, milk, butter, cinnamon, vanilla and salt until smooth, then pour into the prepared baking dish.
Prepare the streusel:
Combine the oats, flour, brown sugar, pecans, cinnamon and pinch of salt in medium bowl.
Cut in the cold butter in with a pastry blender, fork, or your fingers, until it's in pea-sized clumps.
Sprinkle the streusel evenly over the top of the butternut squash filling and bake at 350 degrees F for 45 minutes or until the streusel has browned and puffed up in the center.
Cool on a wire rack for about 10 minutes, then serve.
Notes
Pro tip: The butternut squash purée is the most time consuming part of this recipe, but it really sets this apart. It adds more flavor and texture than canned and it can be made up to 3 days in advance!
Make this butternut squash casserole dairy and gluten-free! Substitute the butter with vegan butter, and the all purpose flour may be substituted with gluten-free 1 to 1 flour or a combination of oat flour and almond flour.
The maple syrup may be substituted with your favorite sweetener, and the brown sugar may be substituted with coconut sugar to make this refined sugar free.
Assemble the entire casserole in advance and bake when you're ready.