PREP: preheat oven to 400°F. Line a baking sheet with parchment.
In a large bowl, whisk together the flour, sugar, baking powder, salt, and cinnamon. Slice the butter into pieces and work the pieces into the flour mixture with a pastry cutter or a fork.
Mash the bananas and if necessary add milk to equal a cup. Stir the yogurt in and add to the flour mixture. Fold in the walnuts.
Line a small wooden breadboard or a cutting board with parchment paper and lay the dough on top, flatenning it out to about 1-inch thick. Cover with a piece of wax or parchment paper and freeze the dough for about 30 minutes.
Peel off the top layer of parchment and slice the scones into squares or wedges. Lay scone slices on prepared baking sheet and bake for 25-30 minutes or until scones are golden brown. Cool scones while you make the glaze.
Melt the butter in the microwave or small pan. Add the milk, brown sugar, and vanilla. Stir until the sugar and melted. Whisk in the powdered sugar along with the cranberries.
Drizzle the glaze over the scones just before serving.
Glaze is sticky and hardens as it cools. Only glaze as many scones as your want to consume. Unglazed scones can be frozen and re-heated in the microwave or toaster oven.