2tablespoonsorange liqueur(such as Cointreau, Grand Marnier, or triple sec)
2tablespoonslight or dark brown sugar
Finely grated zest and juice of 1 orange
1teaspoonkosher salt
For the Streusel Topping:
⅔cupall-purpose flour
½cuplight or dark brown sugar
½teaspoonkosher salt
¼cup(½ stick) unsalted butter(chilled; cut into small pieces)
Instructions
Preheat the oven to 400 F. Line a rimmed baking sheet with foil or parchment paper.
Place the squash halves cut side down on the baking sheet. Bake the squash for about 1 ¼ to 1 ½ hours until they are completely soft inside; a sharp knife should be able to slide in with almost no resistance at all. Remove from the oven and let sit until cool enough to handle, about 30 minutes.
Scoop out the flesh from the butternut squash. Either run the squash through a food mill or a ricer or mash in a large bowl until smooth. Blend in the melted butter, orange liqueur, brown sugar, orange zest and juice, and salt until the mixture is smooth. Transfer the squash mixture to a 1 ½ to 2-quart shallow baking dish.
Make the Streusel Topping: In a small bowl, stir together the flour, brown sugar, and salt. Use your fingers to blend in the bits of chilled butter, rubbing everything together until it is crumbly but with pea-sized bits still present. Distribute the topping evenly over the squash.
Bake for about 30 minutes until the topping has turned golden brown and the squash is hot throughout. Let sit for 10 minutes before serving.
Notes
You can make the filling up to 2 days ahead of time and spread it in the pan. Cover with plastic wrap and store in the refrigerator.
Likewise, the streusel topping can be made a couple of days ahead of time and stored in a container in the fridge. Bring the butternut squash mixture to room temperature while you preheat the oven, and sprinkle the streusel over the top. Bake and serve hot.
If you want to make it all the way through ahead of time, it can be reheated for about 20 minutes in a 350-degree oven until hot throughout and the top has re-crisped.