Toast your hazelnuts (I usually do this at 350 F on a baking sheet for 8-10 minutes).  As soon as they come out of the oven, place them in a clean kitchen towel and close it up (like a bag), let it sit a minute, then you can use the towel to gently rub the skins off.  Roughly chop and set aside.

Chop up your chocolate into small chunks or slivers and set aside.

Melt the butter.  Add to a large mixing bowl (I don't feel the need to get my mixer out for this) along with both sugars, the vanilla, and the miso.  Whisk until fully combined and the mixture becomes glossy (about a minute).

Add the eggs, one at a time, and whisk until smooth and silky.

Add the flours, baking soda, baking powder and cinnamon, and use a spoon to mix.  Only mix until just combined, you don't want to overmix.

Add the chocolate chunks and hazelnuts, and stir in until just combined.

Refrigerate for 1 hour before baking.  The dough does really need this.  Preheat the oven to 355 F (180 C) and line a large baking sheet with parchment paper.

Spoon about 3 tablespoons of dough into your hand and roll into a rough ball.  Place on baking sheet, leaving room to spread.  Sprinkle (carefully, so it stays on) with a pinch of flaky salt.

Bake for 9-12 minutes. About 7 minutes in, open the oven door. Pick up the cookie sheet and bang it onto the oven rack a couple of times, so the cookies deflate and spread a little more. Bake until golden, becoming crisp around the edges and still a little gooey looking in the center.

Remove from the oven and bang one more time on the stovetop.  Let cool for a few minutes, then move to a cooling rack.  Serve warm.