Peel, deseed and cut pumpkin into medium sized chunks. Steam for 15 minutes until soft. Drain water from pot, then leave pumpkin in the same pot to dry and cool off slightly.
Blend the pumpkin pieces in a food processor until it reaches a puree consistency. Mash the pumpkin pieces well if you do not have a food processor. Set aside until cooled to room temperature.
Preheat oven to 180 degrees Celcius.
Grease with butter or line a large, round baking pan with baking paper.
Using an electric mixer, whisk together butter, sugar, salt and Pumpkin Pie Spice until light and creamy. Add in the eggs one at a time and continue mixing until well combined.
Stir in the pumpkin puree, then lightly fold in flour, chopped pecans and buttermilk in small batches, until all ingredients are well combined.
Transfer to your prepared baking pan and bake for 1 hour. Baking times vary, so keep an eye on yours. The cake is done when a toothpick or skewer stick inserted in the center comes out clean.
Remove from oven and let the cake cool for 10 minutes before turning out onto cooling rack.
While the cake is cooling, whisk the maple syrup, lemon juice and melted butter in a small bowl until smooth. Gently brush the glaze all over the cake with a pastry brush until the glaze is gone as most of it will soak in. Allow cake to cool completely. Decorate with remaining pecans.
