Steel Cut Oat & Greek Yogurt Blueberry Scones

Rinse oats under cold running water (about 4 times), until the water runs clear and drain. Add to a small bowl along with milk. Refrigerate for 30 minutes while you are getting other ingredients ready. Transfer butter from fridge to the freezer for 15 minutes.Preheat oven to 425 F degrees and get baking sheet ready. Place a piece of parchment paper fitting the baking sheet on the cutting wooden board and lightly sprinkle with flour to coat the middle, in a shape of a 8-10" circle.In a medium bowl, whisk egg whites for 30 seconds until a bit foamy. Add greek yogurt, agave nectar and vanilla extract, and whisk to combine. Refrigerate.Meanwhile, in a large mixing bowl add white flour, whole wheat flour and baking powder, and mix to combine. Grate butter into the same bowl and mix pressing the butter pieces into flour with spatula. Add the liquids mixture from step 3, soaked oats from step 1 and mix until the dough forms. Add blueberries and gently fold them into the dough. Do not press hard not to crush the blueberries. The dough will be sticky.Transfer dough to a lightly floured parchment paper sheet, lightly flour and roll or pat into a circle about 3/4" - 1 " thick. If the dough is too sticky add a bit more flour. As long as you can form it into a circle it's fine. Sticky dough means moist scones.Using lightly floured sharp fillet or long knife, cut the circle into 12 triangles. Make sure to cut through and I suggest cut twice each line. Do not separate into individual scones!In a small bowl, beat 1 egg white until foamy. Brush the scones with egg wash and sprinkle with brown sugar.Pick the parchment paper with scones by the sides and transfer onto the baking sheet. Bake for 18 minutes or as soon as scones become lightly brown. Remove from the oven and transfer to a cooling rack. Cool for 10 minutes before separating. If necessary, use the knife to separate the scones. Serve warm or at room temperature.