Preheat oven to 400 degrees Fahrenheit (200 degrees Celsius) and line a baking sheet with parchment paper.

In a large mixing bowl, whisk together the whole wheat flour, whey protein isolate, baking powder, and salt.

Incorporate the chilled butter cubes into the dry mixture using a pastry cutter or fork until it resembles coarse crumbs.

Add the Greek yogurt and egg to the bowl, folding gently until a shaggy dough forms.

Turn the dough onto a lightly floured surface and pat into a rectangle approximately 1-inch thick.

Using a 2.5-inch biscuit cutter, punch out 6 rounds and place them on the prepared baking sheet.

Bake for 12 to 15 minutes or until the tops are golden brown and the internal structure is firm.

Transfer to a wire rack and allow to cool for 5 minutes before serving.