Use the large holes of a box grater to grate the butter. Transfer to a small bowl and place in the freezer until it goes into the dough.

In a medium bowl, whisk together the heavy cream, the discard, and egg yolk until smooth. Place in the refrigerator until it goes into the dough.

Line a sheet pan with parchment paper.

In a large bowl use a fork to combine the flour, 67 grams (⅓ cup) sugar, 37 grams (¼ cup) oats, baking powder, and salt. Use the fork to toss the grated butter to coat in the flour mixture (no need to work in the butter any more than this), then stir in the cream mixture until just combined. Knead the dough in the bowl a few times to bring it together.

Dump the dough onto a work surface and pat it together to form a roughly 2-inch tall disk. Cut the disk into 8 wedges. Arrange the wedges evenly on the prepared sheet pan. Freeze the scones until firm, about 30 minutes or up to 8 hours. If not baking after 8 hours, wrap the scones in plastic wrap, then place in a freezer-safe bag. Freeze for up to 2 months.

When you’re ready to bake, preheat the oven to 375ºF (190ºC) with a rack positioned in the center. Brush each scone with a bit more cream, then sprinkle with 19 grams (2 tablespoons) oats, then 25 grams (2 tablespoons) sugar. 

Bake until the scones are puffed and deeply golden, 22 to 27 minutes (if baking scones that have been frozen for more than 8 hours, they may need an additional 5 or so minutes.) Let cool on the sheet pan for 5 minutes before devouring, or cool completely. 

Store in an airtight container at room temperature for up to 2 days; or wrap individually in plastic wrap and a freezer-safe bag and freeze for up to 2 months. Reheat room temperature scones in a 350ºF (177ºC) oven until warmed through, about 10 minutes; defrost frozen, baked scones for 1 hour at room temperature or overnight in the refrigerator first, then warm through.