Preheat the oven to 400°F (200°C). Line a baking sheet with parchment paper and set aside.
In a large bowl, whisk together the flour, granulated sugar, baking powder, and kosher salt.
Add the cold, cubed butter to the flour mixture. Use a pastry cutter or your fingers to cut the butter into the dry ingredients until the mixture resembles coarse crumbs with some pea-sized bits remaining.
In a medium bowl, whisk together the egg, heavy cream, and vanilla extract.
Add the wet ingredients to the dry, and mix gently with a spatula until a shaggy dough forms. It’s okay if the dough looks a little dry and crumbly.
Fold in the chopped bananas carefully, mixing only until they are evenly distributed. The dough will be slightly sticky.
Turn the dough out onto a lightly floured surface. With floured hands, gently pat it into an 8-inch circle that is about 1 inch thick.
Use a bench scraper or sharp knife to cut the dough into 6 to 8 wedges (I made 8). Transfer the wedges to the prepared baking sheet, spacing them slightly apart.
Bake for 13 to 17 minutes, or until the tops are lightly golden and the scones are set.
Remove the scones from the oven and allow them to cool slightly on the baking sheet while you make the glaze.
In a small bowl, whisk together the confectioners’ sugar, maple syrup, ground cinnamon, and enough milk to create a drizzleable consistency.
Drizzle the glaze over the warm or cooled scones before serving.