8 1/2 ounces flour (scant 2 cups) — substitute up to a (slightly scant) quarter rye or whole wheat pastry flour
1/2 tsp baking soda
3/4 tsp baking powder
10 Tbsp (5 ounces) unsalted butter, softened to room temperature
5 ounces (2/3 cup) brown sugar, packed
4 ounces (1/2 cup plus 1 Tbsp) granulated sugar
1 large egg
1 tsp vanilla
1 tsp soy sauce
1 1/2 tsp ginger juice (it's easiest to grate the ginger, then press it through a garlic press to extract the juice)
6 ounces chocolate of your choosing, chopped into small cubes and bits (~1 cup)
~1/2 cup black sesame seeds
coarse salt (optional)
Sift together the flour(s), soda, powder and salt. Set aside.
Place the butter in a mixer or large bowl, and beat together with the sugars until very light. Add the egg, vanilla, soy sauce, and ginger juice, and stir until well combined. Add the flour mixture, stir until just mixed, and then add the chocolate and stir to distribute evenly. Place in a bag or covered container, and chill 2-3 days.
When you're ready to bake, preheat your oven to 350 degrees, and line a few baking sheets with parchment (or grease them well and hope for the best). Scoop the dough out into cookies of the size you prefer — large, 3-inch balls of dough easily make for a nice crisp-outside-gooey-inside consistency, but I find you can arrive at something similar if you make small cookies and watch them like a hawk. Roll in the sesame seeds to give a fairly heavy coating, and place on the prepared sheets. If you fancy a bit more salt in your sweet, you can also top each cookie with a whisper of coarse salt.
Bake until golden brown on the edges yet soft, 10-15 minutes depending upon cookie size. Let the cookies cool on the sheet for a couple minutes until they firm up enough for you to move them, then transfer to a rack to cool completely (it's difficult to end up with soft cookies if you don't pull them soon enough). Devour when warm, with milk (or, if you'd like to keep with the theme, soymilk).