Note
1: In a medium saucepan over medium heat, melt the butter with the dry milk powder, stirring and swirling the pan often, until the butter foams, turns golden brown and smells nutty, about 5 to 7 minutes.
Pour into a large bowl and set aside to cool, about 15 minutes.
2: In a medium bowl, whisk together the plain flour, buckwheat flour, baking soda, and salt.
Line 3 large baking sheets with greaseproof/parchment paper, if baking all at once.
Tip: If baking in batches, line one quarter sheet pan with parchment and pull out a half sheet pan to cool or freeze the rest.
3: Add the sugars to the melted brown butter; mix until combined.
Add the egg, egg yolk and vanilla extract and stir until combined. Add the flour mixture and stir until well combined.
4: Stir in the chocolate.
Working one at a time, scoop out about 82 grams of the dough and roll into a ball. Place the balls on the prepared baking sheets, and chill for 1 hour and up to 24 hours.
Tip: If you don’t want to bake all of these at once, put some of the rolled dough balls on a covered baking sheet in the freezer until frozen.
5: When ready to bake, heat Ooni Volt to 175 °C degrees.
Bake just until the edges start to turn golden, rotating halfway through the bake at about 7.5 minutes, for a total bake of about 15 minutes.
6: Remove from the oven and sprinkle cookies with flaky sea salt to taste.
Put the baking sheets on a cooling rack and let sit for about 10 to 15 minutes before enjoying. Store cookies in an airtight container at room temperature for up to 3 days.
