Work in the butter just until the mixture is unevenly crumbly; it's OK for some larger chunks of butter to remain unincorporated.
Stir in the chopped apple and chips.
In a separate mixing bowl, whisk together the eggs, vanilla, and applesauce.
Add the liquid ingredients to the dry ingredients and stir until all is moistened and holds together.
Line a baking sheet with parchment; if you don't have parchment, just use it without greasing it. Sprinkle a bit of flour atop the parchment or pan.
Scrape the dough onto the floured parchment or pan, and divide it in half. Gently pat and round each half into a 5" to 5 1/2" circle about 3/4" thick.
To make the topping: Stir together the coarse sugar and cinnamon. Brush each circle with water or milk, and sprinkle with the topping.
Using a knife or bench knife that you've run under cold water, slice each circle into 6 wedges.
Carefully pull the wedges away from the center to separate them just a bit; there should be about 1/2" space between them at their outer edges.
For best texture and highest rise, place the pan of scones in the freezer for 30 minutes, uncovered. While the scones are chilling, preheat the oven to 425°F.
Bake the scones for 18 to 22 minutes, or until they're golden brown. When you pull one away from the others it should look baked all the way through; the edge shouldn't look wet or unbaked.
Remove the scones from the oven and cool briefly on the pan. Serve warm.
Wrap any cooled leftover scones securely and store at room temperature for several days; freeze for longer storage.