bowl, stir together all pecan layer ingredients and set aside.
in a medium bowl, stir together all dry ingredients — flour, baking powder, baking soda, salt, cinnamon, nutmeg. set aside.
in a small bowl, stir together buttermilk, bourbon, vanilla extract, and molasses.
in a large bowl (preferably the bowl of your stand mixer), beat butter and sugar on medium speed until light and fluffy. add eggs one at a time, scraping down after each addition. add 1/2 of the dry goods, then half of the wet goods, then half of the pumpkin, then mix well. repeat.
spoon half the pumpkin batter into the pan. sprinkle the pecan layer on top first half of batter. 