In a large bowl, whisk the flour, sugar, baking powder, cinnamon, and salt. Grate your frozen butter on the finer side. Add butter to flour bowl and toss just until combined.
In a small bowl, whisk the milk, egg, and vanilla together. Pour over the flour mixture and mix until moistened.
Gently fold in the chocolate chips. Add a touch more flour 1 -2 Tablespoons at a time if needed. You don't want the dough too wet but you also don't want it dry. It will be a little sticky. Form the dough into a ball with floured hands and transfer to a silicone or parchment paper covered baking sheet.
Press into a neat 8″ disc and cut into 8 equal wedges with a very sharp knife. I like to separate my wedges just slightly so they bake more evenly.
Bake at 400 degrees for 20-25 minutes or until slightly browned and insides are done.