Preheat oven to 375 degrees. Line a sheet with parchment paper. Combine the buttermilk and vanilla in a small bowl and set aside.

Put the flour, granulated sugar, baking powder, baking soda, orange zest, nutmeg, cinnamon and 1/2 teaspoon salt in a food processor and pulse until combined. Add the butter and continue to pulse until the mixture looks like fine meal.

Add the pecans and pulse once. Add the buttermilk mixture and pulse 3 or 4 times, or until the mixture is just moistened.

Turn the dough out onto a lightly floured surface and gently knead until it just forms a ball. Transfer to the prepared baking sheet and pat into an 8-inch round, about 3/4 inch thick. Brush with buttermilk and bake until golden, about 25 minutes.

Let cool on the baking sheet for 2 minutes, then transfer to a rack.

Mix the confectioners' sugar, maple syrup and a pinch of salt in a small bowl until smooth. Drizzle over the scones. Cut into 8 wedges.