Make the Brownie Base

1. Line a 9×9-inch baking dish with parchment paper and lightly coat it with nonstick spray.
2. In a saucepan over low heat, melt ¾ cup butter and ⅔ cup chocolate chips until smooth.
3. Whisk in the cocoa powder and optional espresso powder until well combined.
4. Pour the mixture into a large mixing bowl and let it rest for a few minutes to cool slightly.
5. Stir in the sourdough discard, granulated sugar, brown sugar, and vanilla until the mixture is smooth and slightly thickened.
6. Add the eggs one at a time, whisking thoroughly after each addition until fully blended.
7. Gently fold in flour, salt, and the remaining 1 cup chocolate chips—stop folding once no streaks of flour remain.

Optional long ferment: Cover and refrigerate overnight to develop tang and depth. Before baking, remove the batter and let it sit for 30 minutes at room temperature.

2. Bake

1. Pour batter into the prepared pan, smoothing the top.
2. Bake at 350 °F (175 °C) for 32–36 minutes—edges should be set; the center will show moist crumbs.
3. Remove and let brownies cool fully in the pan before frosting.

3. Prepare German Chocolate Frosting

1. In a medium saucepan over medium heat, whisk together the butter, brown sugar, egg yolks, vanilla extract, and evaporated milk.
2. Cook, whisking constantly for about 10 minutes, until mixture thickens and turns a rich caramel color.
3. Take the pot off the heat and gently stir in the shredded coconut, chopped pecans, and a pinch of salt.
4. Let frosting cool ~10 minutes before spreading evenly over cooled brownie layer.

4. Chill and Drizzle

1. Chill the frosted brownies in the refrigerator for a minimum of 2 hours to allow the topping to fully set.
2. For an optional topping, microwave ¼ cup of chocolate chips with 2 teaspoons of coconut oil for 30 seconds, stir until smooth, drizzle over the brownies, and refrigerate again until set.
3. Once set, use the parchment paper to lift the brownies from the pan, cut them into squares, and serve.