Whisk together the egg, vanilla, and buttermilk in a medium bowl. Stir in the 1 teaspoon of orange zest and the orange juice. Hold this mixture aside.
Blend the dry ingredients and the butter:
Whisk together the flour, sugar, baking powder, cardamom, baking soda, and salt in a large bowl.
Use a grater to grate the cold butter over the dry mixture. Then, use a pastry blender or two forks to mix the butter in, so that no clumps remain.
Combine the wet and dry mixtures:
Pour the egg-buttermilk mixture into the large bowl of dry ingredients and butter. Use a large spoon to stir everything together, JUST until most of the dry ingredients are mixed in.
Turn out this dough and any remaining dry bits onto a lightly floured surface. Squeeze and fold the dough a few times until you have a craggy ball of dough. (Don't overmix here.)
Shape the dough into a round that's about 7 inches in diameter, and about 1½ to 2 inches thick.
Chill the dough:
Place the dough round on a parchment paper-lined baking sheet, and loosely cover it with a piece of plastic wrap. Place the pan in the fridge to chill for 15 minutes.
Preheat the oven to 400° F.
Cut the dough:
Use a sharp knife to slice the dough round into 8 even wedges. Space the wedges apart from each other on the baking sheet.
Brush the tops of the scones with a little buttermilk.
Bake the scones:
Pop the pan of scones into the oven, and bake them for 20 minutes. They should be browned and baked through.
Prepare the Maple Glaze:
While the scones bake, warm up the maple syrup in a medium-sized heat-proof bowl in the microwave oven. Whisk it together with the melted butter.
Blend in the confectioner's sugar using a handheld mixer, adding the sugar a ½ cup at a time. Whip the ingredients together until the glaze is smooth and thick.
Serve the scones:
The scones can be served warm or at room temperature. Spoon Maple Glaze over the tops, and add a few pieces of orange zest as a colorful little flourish. Dig in!
Notes
Scones have the best texture when the ingredients stay cold and the dough isn't overhandled. So stir and squeeze the dough just enough for ingredients to hang together.
I love Grade A Dark pure Vermont maple syrup in the glaze, for the stronger and sweeter flavor. Feel free to try other grades, but make sure you're using REAL maple syrup. No fake stuff!