Preheat your oven to 175°C (350°F). Grease a 9x5 inch loaf pan with butter and dust lightly with cocoa powder to prevent sticking.
In a mixing bowl, sift together the flour, cocoa powder, and baking powder until evenly combined. This ensures a smooth, lump-free batter.
In a large bowl, beat the softened butter and sugar with a mixer on medium speed until the mixture is pale, fluffy, and fragrant, about 3-4 minutes. You’ll see it lighten in color and feel soft to the touch.
Add eggs one at a time, beating well after each addition. The mixture may look slightly curdled, but that’s normal and helps incorporate air for a tender crumb.
Stir in the vanilla extract for a warm, sweet aroma. Then, lower the mixer speed and alternately add the dry ingredients and milk, starting and ending with the dry. Mix just until combined—overmixing can make the cake dense.
Pour the batter into the prepared loaf pan, smoothing the top with a spatula. Lightly tap the pan on the counter to release any air bubbles trapped in the batter.
Bake for 50-55 minutes, checking doneness with a toothpick inserted into the center. It should come out with moist crumbs, not wet batter. If it darkens too quickly, tent with foil after about 30 minutes.
Once baked, turn off the oven and let the cake cool in the pan for 10 minutes. Then, transfer it to a wire rack and cool completely before slicing to let the crumb set.
Allow the cake to cool fully, about 30 minutes, before slicing. Serve plain or dusted with powdered sugar, or enjoy with a dollop of whipped cream or a drizzle of chocolate glaze.
