Place an oven rack at the lower third position. Preheat oven to 350˚ F. Line an 8.5 x 4.5-inch loaf pan with parchment paper laid crosswise, then generously butter the exposed ends of the pan. Set aside.
Brown the butter in a small saucepan over medium heat. Do not get distracted during the several minutes it takes to achieve cooking the milk solids in the butter to a warm, toasty brown. Stir frequently for even cooking and to avoid scorching. The browned bits should reach a light brown. Remove from heat and transfer into a large mixing bowl to prevent over-cooking, which results in a sharp, acrid taste.
While the browned butter cools slightly, measure the flour, baking soda, salt, baking powder and spices into a medium bowl. Gently whisk to thoroughly combine. Set aside.
To the large bowl of browned butter, add the 3/4 cup of granulated sugar and 2 eggs. Whisk until well combined and slightly aerated; then add the vanilla extract and shredded Delicata squash. Mix well with a spatula. Add the flour mixture all at once and stir to combine with the spatula. Mix only until the dry ingredients are barely incorporated and take care to avoid over-mixing. Fold in the nuts.
Pour the batter into the prepared loaf pan. Place the slices of Delicata squash on top, if using, then lightly sprinkle the turbinado sugar atop the squash slices.
Bake for about 1 hour, or until a toothpick inserted in the middle of the loaf comes out clean.
Cool in the pan for about 10 minutes, then remove from the pan and complete cooling on a wire rack.