
Made with AI
Preheat the oven to 175°C (350°F). Grease and line the base of a 20 cm (8-inch) round cake pan with parchment paper.
In a medium bowl, whisk together the all-purpose flour, whole-wheat flour, cocoa powder, baking powder, and salt until evenly combined.
In a large bowl, beat the softened butter and light brown sugar for 2–3 minutes, until creamy and slightly lightened.
Add the egg and beat until fully incorporated, scraping down the sides of the bowl as needed.
Add the dry ingredients in three additions, alternating with the milk in two additions. Mix gently after each addition, beginning and ending with the dry ingredients. Stop mixing as soon as a thick, uniform batter forms.
Fold in the chopped dark chocolate, reserving a small amount for the top if desired.
Transfer the batter to the prepared pan and spread it into an even layer. Scatter the reserved chocolate over the surface.
Bake for 25–32 minutes, or until the edges are firm and a skewer inserted into the center comes out with a few moist crumbs but no wet batter.
Let the cake cool in the pan for 15 minutes, then carefully transfer it to a wire rack to cool completely. Slice and serve at room temperature.