Place a sifter in the middle of a large bowl. Pour the flour, brown sugar, white sugar, nutmeg, baking powder, baking soda and salt into the sifter. Sift the ingredients together. Cut the cold butter into the dry mixture, using a pastry blender or two forks. There will still be small chunks of butter throughout the dough. Use a wooden spoon to stir in mashed banana, egg, vanilla extract and cream. Mix until barely combined. Fold in the butterscotch chips.

Place a piece of parchment paper on the counter and sprinkle with flour. Pour the mixture out onto the parchment paper and form into a circle approximately 1-1/2 inches tall. Use a sharp knife to cut into 8 wedges. Slide a flat baking sheet underneath the parchment paper and transfer the scone dough into the refrigerator to chill for 30-60 minutes.

Once scone dough has chilled, pre-heat the oven to 350-degrees and prepare the topping. In a small bowl, mix together the egg, cream and vanilla extract. Use a pastry brush to brush the tops of the scones and sprinkle coarse sugar on top (if using).

Bake scones in 350-degree oven for 35-40 minutes or until the tops are light brown and crisp and the scones are baked through.

Remove baked scones from the oven and re-cut the scones using the same cut marks made before baking. Let scones rest on the cookie sheet for 10-minutes before transferring the scones to a wire rack to finish cooling completely.