Preheat the oven to 425 degrees (F). Line a baking sheet with parchment paper or a silicone mat. Set aside.
In a large bowl, whisk together the flour, sugar, baking soda, baking powder, salt, and Earl Grey tea.
Using clean, dry hands, work the butter into the dry mixture. There should be pea-sized pieces of butter with a few slightly larger chunks.
Make a well in the center of the dry ingredients and add the vanilla and 1 cup of the buttermilk. Begin to stir and add the last 1/4 cup slowly, you may not need all of it. The mixture should not be too wet.
Turn the mixture out onto a clean and floured surface and gather the dough together. Pat the dough into a circle about 1 inch thick. Using a sharp knife, cut the circle into equal-sized triangles and place on the prepared baking sheet.
Brush the top of each scone with heavy cream and sprinkle with the coarse sugar. (OPTIONAL)
Bake the scones for about 17-20 minutes or until golden brown. Let the scones cool slightly before glazing.