Preheat oven to 350 degrees F. Line a baking sheet with parchment paper.
In a large mixing bowl, add the flour, sugar, baking powder, baking soda, salt & cinnamon. Whisk well until combined.
Add the pieces of cold butter and cut into the dough using a pastry cutter or fingertips until the mixture resembles small peas.
In a separate medium bowl, whisk together the egg, 3/4 cup of the butter milk, and the maple extract. Slowly add the wet ingredients into the dry ingredients and then gently knead the dough with your hands until the dough starts to come together.
Add the walnuts the dough and knead gently to incorporate.
Move the dough onto a floured surface, and divide it in half. Round each half into disks to be about 1 1/2" thick.
Using a knife or bench knife that you've run under cold water, slice each circle into 6 wedges. Move the slices onto the prepared baking sheet.
Bake the scones for 25 to 30 minutes (rotating the baking sheet halfway through the baking time), or until they're golden brown. When you pull one away from the others, it should look baked all the way through; the edge shouldn't look wet or unbaked.
Remove the scones from the oven, and cool briefly on the pan.
When the scones are completely cool, wrap them in plastic and store at room temperature for up to 3 days. To reheat room-temperature scones, place on a baking sheet, tent lightly with foil, and warm in a preheated 350°F oven for about 10 minutes.