Preheat oven to 400 degrees and line a baking sheet with parchment paper.
In a large bowl, whisk together flour, granulated sugar, brown sugar, baking powder, baking soda, cinnamon, nutmeg, and salt.
Cut in butter with a pastry blender or fork (or your hands), until pea-size pieces form with some larger chunks remaining. Mix in chopped apple.
In a small bowl, whisk together yogurt or sour cream, milk, egg, and vanilla extract. Using a spatula, fold the wet ingredients into the dry mixture until just combined.
Place dough on a lightly floured surface and flatten it into a rough rectangle about 1" thick. Sprinkle cinnamon sugar swirl mixture over half the dough and fold the other half down and press gently. Fold the dough once more.
Form the dough into a circle about 1" thick. Slice dough into 8 triangles (I like to use a bench scraper to do this) and place on prepared baking sheet. Brush scones lightly with milk or cream and sprinkle with coarse sugar if desired.
Bake for 17-21 minutes, until scones are just turning golden around edges.
Let scones cool before drizzling with maple cinnamon icing.