1. Adjust oven rack to lower-middle position and preheat oven to 400 degrees. Line a baking sheet with parchment paper.
2. In a medium bowl, mix flour, baking powder, baking soda and salt. Using the large holes of a box grater, grate the frozen butter into flour mixture. Use the tips of your fingers to work in the butter (the dough will be crumbly).
3. In a small bowl, whisk the sour cream and egg until smooth.
4. Using a fork, stir sour cream mixture into flour mixture until large dough clumps form. Stir in the cheese, bacon and chives until they are well incorporated into the dough.
5. Use your hands to press the dough against the bowl into a ball. At first it may seem like there isn’t enough liquid, but as you press, the dough will come together.
6. Place the dough on a lightly floured surface and pat into a 7-inch disk about 3/4-inch thick. Use a sharp knife to cut the dough into 8 triangles; place the scones onto prepared baking sheet. Use a pastry brush to lightly brush the tops of the scones with heavy cream, this will help you achieve a nice golden brown color. Bake until golden, about 15 to 17 minutes. Cool for 5 minutes and serve warm or at room temperature.
Notes
If you really want to take these to the next level, slice a scone in half and top each half with a fried egg.These scones are best served the day they are made.