Preheat the oven to 425°F (220°C). Line a baking sheet with parchment paper or lightly grease it; set aside.

Prepare the oats by grinding them in a food processor or blender until they reach a coarse flour-like consistency. A few larger oat pieces may remain.

In the bowl of a stand mixer fitted with the paddle attachment (or in a large bowl by hand), combine the all-purpose flour, ground oats, granulated sugar, salt, and baking powder. Mix briefly to incorporate.

Add the cold butter to the dry ingredients. Toss to coat, then mix on medium-low speed (or use a pastry cutter or fork) until the mixture resembles coarse crumbs, with pea-sized pieces of butter visible throughout.

Add the maple syrup to the flour mixture and mix briefly.

In a separate small bowl or measuring cup, whisk together the egg, heavy cream, and maple extract until well combined.

Pour the wet mixture into the dry ingredients and mix until the dough just comes together. Do not overmix.

Fold in the chopped pecans and mix gently until evenly incorporated.

Transfer the dough to a lightly floured surface. With floured hands, gently knead and pat the dough into a circle approximately 8 to 10 inches in diameter.

Cut the circle into 8 even wedges and place them on the prepared baking sheet, spaced slightly apart.

Bake the scones for 13–15 minutes, or until they are lightly golden on the edges and fully set in the center. Remove from the oven and allow to cool on a wire rack.

Prepare the maple glaze by whisking together the powdered sugar, maple extract, and milk (or water) until smooth. Once the scones have cooled slightly, brush the glaze evenly over the tops of each scone. Allow to set.

While the maple glaze firms, prepare the powdered sugar drizzle by whisking together its ingredients until smooth. Drizzle over the glazed scones. Allow the icing to fully set before serving, approximately 1 hour.