Preheat oven to 400℉.
In a medium bowl, combine dry ingredients - flour, sugar, baking powder, baking soda, salt, cinnamon and nutmeg.
Slice cold butter (make sure it is cold!) into large cubes.
Cute cold butter into dry flour mixture by using a pastry cutter or grater and then combining them, or using a food processor to pulse butter into the dry mixture. At the end, flour mixture should be fairly dry with small chunks of cold butter. Do not overmix dough.
In a large bowl, whisk together wet mixture which consist of sour cream, pumpkin puree, vanilla extract and egg.
Pour four/butter mixture into wet mixture. Use hands to fold flour mixture into wet mixture. After combining, mixture should be slightly crumbly, not too wet or sticky. Do not overmix dough. Form dough into a large ball.
Flour surface, and place dough ball on surface.
Press dough down to form a round circle with ~9 inch in diameter.
Slice scones into 8 triangles of approximately the same size. Place each of them on a baking sheet lined with parchment paper, 1-2 inches apart from each other.
Bake for ~17-18 minutes.
While scones are baking, make Maple Glaze by combining melted butter (use microwave to melt it completely until it is in liquid form), maple syrup and powdered sugar.
Once scones are done, cool completely using a baking rack.
Drizzle scones with maple glaze.
Serve and enjoy!