Preheat the oven to 350 °F (175 °C) and line an 8”x8” (20 cm) pan with a piece of parchment paper. Place a medium mixing bowl in the fridge for whipping the heavy cream later.

In a medium mixing bowl, stir together the flour, baking powder, baking soda and salt. Set aside.

In a medium saucepan over medium heat, stir and melt together the sugar, butter and cocoa powder.

Once melted, remove from the heat and stir in the milk, egg and vanilla extract. Mix just until the egg is well combined.

Fold the dry ingredients into the wet. It’s okay if there are small lumps - just not large ones.

Pour into the prepared pan and bake for 13-15 minutes or until a toothpick inserted in the middle comes out with moist crumbs, but no raw batter. A toothpick inserted towards the sides will come out clean.

Remove to a wire rack to cool completely, about 1 hour.

Whip the cream using a hand mixer or stand mixer. Begin at low speed to avoid splattering and gradually increase the speed. You'll notice the cream thickening and increasing in volume. Be careful not to overwhip; you want stiff peaks.

Cut into 9 or 12 bars. Dollop some whipped cream over one of the bars. Sift cocoa powder over the top of the whipped cream.

Store your cocoa bars in an airtight container at room temperature. They’ll stay fresh for about 3 days. Only add the whipped cream before serving.