Preheat your oven to 375 degrees F and prepare a baking sheet with parchment paper or a Silpat liner, set aside.
In a large bowl whisk together flour, salt, and baking powder.
Using your hands work the cold butter into the flour until it's crumbly and the flour is moistened. You can also use a pastry blender.
Stir in shredded cheese, green onions, and ham into the flour mixture.
In a small bowl whisk together eggs, sour cream, and mustard.
Add the egg mixture to the flour and mix together until the dough just comes together. The dough will be sticky.
On a kitchen counter (or large wooden cutting board) sprinkle with lots of flour so the dough will not stick. Coat your hands in flour as well.
Dump the dough onto the counter and pat the mixture into 10 inches long by a 2-inch wide rectangle. Cut the dough into 5 squares and then cut each square diagonally.
Add the scones to the prepared baking sheet, leaving 1 inch between each scone.
Brush heavy cream onto the top of each scone and bake for about 20 minutes until slightly browned and fully cooked.