Preheat oven to 400º.
Line a cookie sheet with parchment paper.
Set aside.
In a large mixing bowl, place flour, granulated sugar, baking powder, baking soda and salt.
Stir or whisk well to combine ingredients.
Add cold butter and cut into mixture with a pastry blender until coarse crumbs form.
Add 1 cup miniature chocolate chips and the walnuts and stir again to combine.
Measure out buttermilk or soured milk in a small measuring cup.
Add vanilla extract and stir to combine.
Pour buttermilk mixture into flour mixture and stir until a soft dough forms.
Transfer dough to a floured bread board and sprinkle dough very generously with more flour.
If dough is too sticky, add additional flour, up to 1/2 to 2/3 cup.
Spread fingers wide and work flour into dough; turn dough over multiple times; working more flour into the dough each time.
Knead five or six times.
Pat dough into a 7-inch round about two inches deep.
Cut the dough into eighths.
Transfer the scones onto the parchment paper-lined cookie sheet.
Combine egg and cream in a small bowl with a whisk.
Brush the tops and sides of each scone with egg/cream mixture.
Sprinkle remaining two tablespoons granulated sugar or turbinado sugar over top of the scones.
Sprinkle remaining ¼ cup miniature chocolate chips over tops.
Gently press chocolate chips into the scone dough.
Bake at 400º for approximately 20-22 minutes, or until a toothpick inserted in center comes out clean.
Cool before adding glaze.
Add glaze and serve.