For GF scones preheat oven to 350 degrees (F). For regular scones preheat oven to 450 degrees (F). Line a cookie sheet with a silicone mat or parchment paper.
In a large bowl, combine the flour, brown sugar, baking soda, baking powder, and salt. Whisk to combine and ensure that no lumps of brown sugar remain.
Using clean hands or two forks, work the cold butter into the flour mixture. The mixture should look like coarse meal with a few pea-sized chunks. Add the chopped walnuts.
Make a well in the center of the ingredients and add the buttermilk and maple extract. Combine the ingredients until the dry mixture is wet. Do not knead the dough.
Turn the dough out on a clean and floured (GF or all-purpose) surface. Gather the dough together into a circle about 1 1/2 inches thick. Using a bench scraper or a sharp knife, cut the dough into 10-12 triangles.
Place the scones on the prepared cookie sheet. For GF scones bake for 15-20 minutes or until golden brown. For regular scones bake for 12-15 minutes or until golden brown.
Remove from oven and allow to cool while you prepare the glaze.