Line 2 large baking sheets with parchment paper.
In a bowl, sift in the flours, baking powder, baking soda, cornstarch, and Hojicha powder. Set aside.
In a stand mixer fitted with the paddle attachment, beat the butter and sugars on medium-high speed until light and fluffy, a few minutes.
Add the eggs and miso. Mix on low speed until just combined, scraping down the sides of the bowl as needed to incorporate the ingredients.
Tip in the bowl of dry ingredients. Mix until a cookie dough forms. Fold the chocolate chips (or chunks) and optional nuts of choice into the cookie dough.
Drop heaping 3/4 cups (about 165 g) of dough onto a baking sheet, about 4 large dough balls on each baking sheet spaced at least 2 inches (5 cm) apart. There’s no need to flatten these dough balls.
Freeze the dough balls, uncovered, for 15 to 30 minutes. Just be sure to increase the baking time by a few minutes if you do. Meanwhile, preheat the oven to 400° F (200°C) with a rack in the center.
Bake for about 15-17 minutes, until the tops are golden and the edges begin to darken. As these are thicc cookies, the centers will be soft and the melted chocolates will be gooey.
Remove from the oven. Cool directly on the baking sheets to allow the cookies to set. Cookies tend to continue to “cook” as they rest on a warm baking sheet. The cookie centers should be soft and gooey but not runny or liquidy. Enjoy!
Store leftover cookies in an airtight container and consume them within a few days. Reheat in the toaster or oven at 350° F (180°C) for a few minutes.
Pro Tip:
1/2 teaspoon of salt may be substituted for the miso if not available. Add the salt to the dry ingredients before mixing it into the wet ingredients.