Preheat the oven to 350°F and line a baking sheet with parchment paper.
In the bowl of your mixer, combine the granulated sugar and butter. Beat on medium speed for two minutes, or until light and fluffy.
½ cup granulated sugar, 3 tablespoons unsalted butter, softened
Add the eggs, brown sugar and molasses. Beat on medium speed just until combined.
2 eggs, room temperature, 1 cup brown sugar, packed, 2 tablespoons molasses
In a medium bowl, combine the flour, baking powder, pumpkin spice, and salt. Stir with a whisk to combine and then add to the bowl of your mixer. Beat on low just until combined.
2 cups flour, 2 ¼ teaspoons baking powder, 1 teaspoon pumpkin pie spice, ¼ teaspoon salt
Add ¾ cup of the walnuts. Stir to combine.
1 cup chopped walnut, toasted
Using a large cookie scoop, portion out dough, leaving about 2 inches apart on the prepared baking sheet.
Bake in the prepared oven for 12-14 minutes or until the cookies are just starting to brown around the edges.
Remove from the oven, cool for 2 minutes on the baking sheet before transferring to a wire rack to cool completely.