1½ cups sugar
¾ cup flour
¾ cup cocoa powder (see note below)
¾ cup butter, melted
½ teaspoon salt (if using unsalted butter)
¾ cup semi-sweet chocolate chips (see note below)
A NOTE ON CHOCOLATE: You’ll notice the list of ingredients is very short. That means the quality of the chocolate makes a huge difference. The chocolate flavor is front-and-center — not the sugar, not the richness, the chocolate. I used Ghirardelli unsweetened cocoa powder, and Ghirardelli semi-sweet chocolate chips.
The assembly is about as easy as you can get. Combine the sugar, flour, salt (if using unsalted butter), cocoa, eggs and melted butter and mix.
Do this by hand, until the dry ingredients are just incorporated into the wet, and stop. You don’t need to beat it, and in fact want to avoid producing gluten from the flour. (Kneading flour produces gluten, the springy protein that makes bread chewy.)
Stir in the chocolate chips.
Line a 9×13 baking dish with parchment. I over-did it a little bit here, because I wanted to be absolutely sure it didn’t stick. As long as you cover the bottom you should be good, as it will pull away from the edges while baking.
Pour the batter and spread it out. Don’t try to spread it like mayo on bread, or you’ll move the parchment around. Poke at it with the tip of a rubber spatula.
Bake at 325° for 20-30 minutes. It’s done when a toothpick inserted in the tallest part comes out clean. Keep in mind you’ve got chips in there. If you hit one with the toothpick it will have melted chocolate on it. You might need to poke a couple of spots to make sure you aren’t hitting a chip.