Instructions

Make the cornflake crunch:

1. Heat oven to 275°.
2. In a medium bowl, with your hands, crush cornflakes to ¼ of their original size. Add milk powder, sugar, and salt; toss to mix. Add butter; toss to coat. (As you toss, the butter will act as glue, binding the dry ingredients to the cereal, creating small clusters.)
3. On a parchment- or Silpat-lined sheet pan, spread clusters and bake for 20 minutes, at which point they should look toasted, smell buttery, and crunch gently when cooled slightly and chewed.
4. Cool completely before storing or using in a recipe. Stored in an airtight container at room temperature, the crunch will keep fresh for one week; in the fridge or freezer, it will keep with one month.

Make the brownies:

1. Preheat the oven to 350 degrees F. Butter the sides and bottom of a 9×13-inch glass or light-colored baking pan. Line the pan with parchment paper.
2. In a medium bowl, whisk the flour, salt, and cocoa powder together.
3. Put the chocolate, butter and instant espresso powder in a large bowl and set it over a saucepan of simmering water, stirring occasionally, until the chocolate and butter are completely melted and smooth. Turn off the heat, but keep the bowl over the water and add the sugars. Whisk until completely combined, then remove the bowl from the pan. The mixture should be room temperature.
4. Add 3 eggs to the chocolate mixture and whisk until combined. Add the remaining eggs and whisk until combined. Add the vanilla and stir until combined. Do not overbeat the batter at this stage or your brownies will be cakey.
5. Sprinkle the flour mixture over the chocolate mixture. Using a rubber spatula (not a whisk), fold the flour mixture into the chocolate until just a bit of the flour mixture is visible.
6. Also fold in 1/2 of the cornflake crunch.
7. Pour the batter into the prepared pan and smooth the top. Sprinkle 1- 2 cups of the remaining cornflake crunch (all of it, or save some for sprinkling on other things, or just eating plain.) Bake in the center of the oven for 30 minutes, rotating the pan halfway through the baking time, until a toothpick inserted into the center of the brownies comes out with a few moist crumbs sticking to it. Let the brownies cool completely, then lift them out of the pan using the parchment paper. Cut into squares and serve.
8. Store at room temperature in an airtight container or wrap with plastic wrap for up to 3 days.