Preheat oven to 400 degrees Fahrenheit. Line a rimmed baking sheet with parchment paper and set to the side.
In a large mixing bowl add the all-purpose flour, baking powder, baking soda, and salt. Stir to combine everything together.
Add butter to the bowl and using your fingers or a pastry blender, mix the butter into the flour mixture until it is the size of peas. Add buttermilk and using a fork or heavy duty spatula, stir the mixture until it forms a shaggy dough.
Turn the dough out onto a lightly floured work surface. Pat the dough into a rectangle, about 1-inch thick. Fold the dough in half then pat it down into a second rectangle. Fold in half once more and pat the dough into an 8-inch by 8-inch square that is approximately 1 inch thick. Cut into 6 triangles or squares.
Transfer the scones to the prepared baking sheet. Brush the top of each scone with the half and half or heavy cream. Sprinkle with a little flaky salt.
Bake scones for 20 to 25 minutes, until they are golden brown and cooked through.
Scones are best enjoyed on the day made. However, you can store any leftover scones in an airtight container or resealable bag for up to 2 days. They can also be frozen for up to 2 months.