Preheat the oven to 375 °F. Line a ½ sheet pan with parchment paper or a silicone baking mat.
In a food processor or blender pulse 3 tablespoons pumpkin seeds with 1 tablespoon granulated sugar to make a chunky powder. This can also be done by hand with a sharp knife. Transfer the seeds to a small bowl. Drizzle 1 teaspoon maple syrup over the seeds and mix to combine. Set the topping aside.
Cut 4 oz unsalted butter into ½" chunks and put it in the refrigerator while you prepare the other ingredients.
In a large mixing bowl, whisk together 12 ½ oz unbleached all purpose flour, 5 oz granulated sugar, 1 tablespoon baking powder, 1 teaspoon ground cinnamon, ½ teaspoon ground ginger, ¼ teaspoon ground cloves, ¼ teaspoon ground nutmeg and ½ teaspoon salt.
In a small bowl or liquid measuring cup mix together 6 oz pumpkin puree, 4 oz buttermilk, 1 teaspoon vanilla extract, ½ teaspoon lemon extract and 1 large egg.
Work the butter into the dry ingredients with your fingers, squashing the chunks of butter into large flakes. Work quickly to avoid melting the butter. Add the pumpkin mixture to the dry ingredients all at once and mix until barely combined. Some loose flour may remain at the bottom of the bowl. DON'T OVER MIX.
Dump the dough directly onto a generously floured surface. Sprinkle the top of the dough with flour and knead the dough just a couple of turns to finish mixing the ingredients. Use plenty of flour as this is a very sticky dough. Using well-floured hands, pat the dough a 8” round that is 1" thick. Use a sharp knife to cut the round into 8 wedges. Don't use a sawing motion, just press straight through the dough with the sharp blade. Wipe the knife between cuts for clean edges on the scones. Transfer the scones to the prepared baking sheet.
Brush the top of the scones with buttermilk. Divide the pumpkin seed topping between the scones and lightly pat on the seeds to hold them in place.
Bake until well-risen and golden brown, about 15-18 minutes. Serve warm or room temperature.