Preheat oven to 350° and line a 9x5 bread pan with parchment paper, leaving a 1-inch overhang for easy removal.
Place the squash in a microwave-safe dish and microwave for 5-7 minutes or until softened. Use a potato masher to mash the squash, removing as many lumps as possible.
Next, whisk the eggs, avocado oil, milk, and vanilla together in a large bowl. Then, add the mashed squash and stir to combine.
In a separate bowl, stir the flour, sugar, baking powder, baking soda, salt, cinnamon, ginger, nutmeg, and allspice together.
Pour the dry ingredients into the wet, and use a rubber spatula to stir. Once there’s only a little bit of flour remaining, add the pecans and stir just until the flour disappears.
Transfer the batter to your prepared bread pan, then bake for 55-60 minutes or a toothpick comes out clean. Leave the bread in the pan for 10 minutes, then carefully remove and transfer to a wire rack. Allow the bread to cool most of the way before adding the glaze.
For the glaze, whisk the powdered sugar and milk together until smooth. Drizzle on bread, sprinkle with extra pecans (optional), slice and enjoy!