1. Place butternut squash into a large pot with enough water to cover. Bring to a boil on the stove over medium-high heat and boil until soft when pierced with a fork.
2. Strain, pressing out any additional water, and continue to let sit in the colander to drain while you prepare the pecan topping.
3. Preheat oven to 350ºF.
4. Place a large, non-stick pan on the stove over medium heat. Add pecans, 1/3 cup syrup, and a pinch of salt. Stir mixture continuously until syrup thickens and evenly coat pecans, about 3–5 minutes. Transfer to a baking sheet lined with parchment paper to cool. Careful not to overcook. If it cooks too long, the syrup will harden like candy on the pecans and be hard to get out of the pan (but makes a really tasty snack!)
5. Squeeze excess water out of the squash and then transfer to a large mixing bowl. Add butter, 3–4 tablespoons syrup (to taste), cinnamon (to taste), and generous pinch of salt (add less if your butter is salted.) Beat mixture with a hand mixer or mash with potato masher until no clumps remain.
6. Transfer mixture to and 8-inch square or round baking pan and top evenly with maple pecans.
7. Place into the oven and bake until hot and bubbly, about 30–40 minutes. Makes about 8–10 servings.

Make Ahead:

1. Casserole can be assembled, without topping, up to 2 days ahead of time, covered and refriegrated. Candied pecans can be made 2 days ahead; store in an airtight container at room temperature. Drain off any excess liquid that may have gathered on top of the squash before topping with pecans and baking.