Instructions — Cake

1. Preheat the oven to 350°F. Grease three 9-inch round cake pans and line the bottoms with parchment.
2. Whisk the flour, baking soda, baking powder, pumpkin pie spice, and salt in a bowl; set aside.
3. In a large bowl, cream the butter and sugar until light and fluffy, about 3 minutes. Add the oil and beat to combine. Beat in the eggs one at a time, then the vanilla and pumpkin puree.
4. Add the flour mixture and milk alternately, beginning and ending with the flour, mixing just until combined — don’t overmix.
5. Divide the batter evenly among the three pans. Bake 25–30 minutes, until a toothpick inserted in the center comes out with a few moist crumbs. Cool in the pans 10 minutes, then turn out onto a rack to cool completely.

Instructions — Maple Buttercream & Assembly

1. Whip the butter until pale and fluffy, about 3 minutes. Add the powdered sugar 1 cup at a time, beating on low, until smooth.
2. Beat in the maple extract, bourbon (if using), and salt. Whip until silky. Adjust: a splash of milk to loosen, more powdered sugar to firm up.
3. Level the cooled layers if domed. Stack with buttercream between each layer, then crumb-coat the outside and chill 15–20 minutes.
4. Finish with a smooth final coat and press the honey-roasted pecans around the sides while the frosting is tacky. Slice with a warm, clean knife.