01 -
Heat the oven to 180°C. Line an 8×8-inch baking pan with parchment paper or aluminum foil, ensuring there is enough overhang for lifting the brownies after baking.
02 -
In a large heat-proof bowl, place the chocolate and butter. Heat in the microwave in 20-second intervals, stirring in between, until fully melted, or place over a saucepan of simmering water, stirring occasionally.
03 -
Add the sugar to the melted chocolate mixture and mix until combined. Add the eggs one at a time, whisking after each addition until fully incorporated.
04 -
Add the ground hazelnuts or almond/hazelnut meal, cornstarch, and salt. Fold gently with a rubber spatula until the mixture is just combined, being careful not to overmix.
05 -
Pour the batter into the prepared pan and bake for 20-25 minutes, until the edges are set but the center remains very soft. Avoid overbaking—the toothpick test should result in moist crumbs, not dry.
06 -
Transfer the pan to a wire rack and allow it to cool completely. Refrigerate for at least 4 hours until fully set, for easier cutting.
07 -
Using the parchment paper, lift the brownies from the pan and cut them into 16 squares. Store in an airtight container in the refrigerator for up to 5 days.