This recipe is one of the most decadent (retro) desserts we found in a tiny Brooklyn bakery.
In a medium bowl, whisk together flour, salt, cocoa powder, chili powder, and cinnamon.
Configure a double boiler (fill a medium saucepan with 2 inches of water and fit a metal bowl on top without letting it touch water; bring water to a boil). Place chocolate and butter in bowl and stir occasionally until both are completely melted and combined, about 6 minutes. Turn off heat, but keep bowl over water and add both sugars. Whisk until completely combined and remove bowl from pan. Let stand until room temperature, about 20 minutes.
Add eggs to chocolate-butter mixture and whisk until just combined. Add vanilla and ginger; whisk to combine. Do not overbeat the batter at this stage or the brownies will be cakey.
Sprinkle flour-cocoa mixture over chocolate mixture. Using a spatula (do not use a whisk!), fold the dry ingredients into the wet until there is just a trace amount of the flour-cocoa mix visible.
Pour batter into the greased pan and smooth the top with the spatula. Bake brownies for 27 to 30 minutes; brownies are done when a toothpick inserted in the center comes out with a few moist crumbs. Cool brownies completely before cutting and serving.