Preheat the oven to 425ºF.
In a large bowl, mix together the dry ingredients. Set aside.
In a small bowl, whisk together the buttermilk, egg and instant coffee. Set aside.
Chop the frozen butter into cubes and add to the dry ingredients. If you have a pastry cutter, use this to cut in the butter until the mixture is like rough sand and the butter is pebble-sized. If you do not have a pastry cutter, you can do this with your hands, but try not to overwork the dough.
Mix in the chocolate chips.
Reserve one tablespoon of the buttermilk mixture, and pour the rest into the flour bowl, along with the vanilla. Using a wooden spoon, mix until dough just begins to form.
Place the dough onto a lightly floured surface and knead a couple of times to fully combine and form into a circle of dough.
Press out in a round circle that is about 3/4 inches thick and then cut into 12 triangles.
Lay out the scones on a baking sheet and brush the tops of the scones with the reserved buttermilk mixture.
Bake for 11 minutes or until the bottoms are lightly browned and the tops are just beginning to brown.
Set the baking sheet on a wire rack to cool while you prepare the glaze.
In a small bowl, add the powdered sugar and instant coffee.
Add the vanilla and half & half and mix until the glaze is smooth.
Drizzle each scone with the glaze and enjoy! While they are best fresh, you may store them in an airtight container for up to 3 days. Heat them in a microwave for 8 seconds to soften them back up.
