Preheat the oven to 425°F and place a rack in the middle position. Line a baking sheet with parchment paper.

On the lined baking sheet, arrange the chopped bacon, diced shallots, and ham. Cook in the oven until crispy, then set aside to cool. Once cooled, place the mixture in the freezer while preparing the dough.

Grate the cold butter and return it to the freezer to keep it chilled, as cold butter ensures flakiness in the scones.

In a large mixing bowl, combine the flour, salt, garlic salt, baking powder, and sugar. Add the grated frozen butter and stir until the mixture is crumbly and the butter is evenly distributed.

Stir in the shredded cheese, minced chives, chilled bacon, ham, and shallots. Mix gently to incorporate.

Gradually pour in the buttermilk, starting with 1/4 cup at a time, and mix lightly by hand or with a spoon. Continue adding the buttermilk in increments until the dough just comes together. The dough should be slightly sticky but not overly wet, as too much liquid can result in tougher scones.

Transfer the dough onto a lightly floured surface and shape it into a rectangle about 1 inch thick. Cut the dough into 12 equal pieces. For even baking, cut into rectangular shapes rather than wedges.

In a small bowl, whisk together the egg and water to create an egg wash. Brush the tops of the scones with the egg wash, and sprinkle with flaky sea salt if desired.

Bake the scones in the preheated oven for 25 minutes or until they turn golden brown.

As soon as the scones are baked, brush them with melted butter and sprinkle additional chopped chives on top for extra flavor.

Store any leftover scones in an airtight container in the refrigerator. To serve, reheat them briefly in the oven for the best texture and flavor.