Preheat oven to 400 degrees. Line a baking sheet with parchment.
Whisk flour, baking powder, salt, black pepper + ground flax together in a large bowl.
Make a well in the center and add the greek yogurt. Using a fork, gently mix the yogurt into the flour until you get a craggy texture.
Dust a work surface lightly with flour and turn out the dough. Knead just until it becomes smooth, being careful not to overwork the dough. Dust a rolling pin with flour and roll it into a disc about 1" thick. Cut out biscuits with a 2-1/2" biscuit cutter and transfer to the baking sheet, leaving space between so they can breathe. Gently combine scraps, re-roll and cut more biscuits.
Bake for 20-22 minutes, until they are golden brown. Allow them to rest of 5 minutes before tearing in.