Preheat the oven to 350°F. Liberally grease and flour a Bundt or tube pan. You can also use a 10-inch round cake or springform pan. Set aside. Combine the flour, baking powder, and salt. Set aside.
Put the butter in a microwave-safe bowl and melt. Stir in the brown sugar, maple syrup, cinnamon, and salt until combined. Add the pecans and set aside.
Using an electric mixer, combine the butter and sugars together until light and fluffy, 2 to 3 minutes.
Add the eggs, one at a time, mixing until combined into the batter. Add the vanilla and mix.
Turn the mixer off and add half the flour mixture. Mix until just combined. Add the buttermilk and mix until smooth. Add the remaining flour and mix until combined.
Spoon the pecan mixing into an even layer at the bottom of the pan. Spoon the batter on top and smooth it out.
Bake in the oven for 35 to 38 minutes, or until a toothpick inserted into the cake comes out clean or with a few moist crumbs. Take the cake out of the oven and set a timer for 10 minutes. When the timer goes off, set a large plate on top of the cake. Using oven mitts, carefully flip the entire cake and pan upside down. Remove the pan.
Allow the cake to cool completely before slicing and serving.