Preheat oven to 375 degrees F. Lightly grease a baking sheet, or line it with parchment paper.
To make the scones: Combine the flours, oats, sugars, baking powder, and salt in a large mixing bowl. With a pastry cutter or a fork, cut the butter into the dry ingredients until the butter pieces are the size of a pea. Stir in the macadamia nuts. Whisk together the egg, milk, and almond extract in a large measuring cup. Make a well in the center of the dry ingredients, and add the liquid all at once to the bowel. Lightly mix with a fork until the dough is evenly moistened; it will comes together but still be a little wet. Don't stir vigorously, or the scones will be tough. Let the dough sit for 5 minutes to allow the oats to absorb the liquid.
Scoop the dough by the generous tablespoon, placing the scones 2 inches apart on the prepared baking sheet. Wet your fingers and smooth out the tops a bit.
Bake until the tops and edges are light golden brown, 25-27 minutes. Remove the scones from the oven and cool on the pan on a rack for 15 minutes before transferring to a rack to cool completely.
Glaze
Whisk together the sugar, zest, and juice in a small bowl until the glaze has no lumps. Brush over the tops of the cooled scones.