Baked Cocoa Birthday Cake
A dense, fudgy cocoa sheet cake baked in the oven and cut into ten squares. Rich chocolate flavor with a pinch of salt, made for a birthday table without any stovetop work.
- Total
- 74 min
- Prep 15 · Cook 39 · Rest 20
- Serves
- 1
- Difficulty
- Easy
You'll practice: Whisking · Folding
- Sweet
- Oven
Instructions
-
Heat the oven to 175°C. Line a 23 x 33 cm baking tin with parchment paper, leaving a little overhang on two sides.
~10 min
Lining with overhang lets you lift the baked cake out cleanly without inverting it.
-
Melt 200 g butter in a small bowl set over the oven's warmth or in short bursts until just liquid, then let it cool for a few minutes so it is warm, not hot.
~5 min
Cooling melted butter prevents it from cooking the eggs when combined.
-
Whisk 200 g sugar, 4 eggs and 0.5 tsp salt in a large bowl for 2 minutes, until the mixture is pale and slightly thickened.
~2 min
Whisking eggs and sugar aerates them, helping the cake rise and become pale and thickened.
Whisking Whisk vigorously for 2 minutes until the mixture is pale and thickened; under-whisking leaves it thin and less aerated.
-
Pour the warm melted butter into the egg mixture and whisk until smooth. Add 150 ml water and whisk again.
~2 min
Whisking Whisk vigorously for 2 minutes until the mixture is pale and thickened; under-whisking leaves it thin and less aerated.
-
Sift 180 g flour and 60 g cocoa over the wet mixture. Fold with a spatula just until no dry streaks remain; the batter will be thick and glossy.
~3 min
Folding gently prevents gluten development, keeping the cake tender rather than rubbery.
The batter is meant to be thick and dense; stop folding as soon as the flour and cocoa disappear, or the cake turns rubbery.
Folding Use a spatula to fold just until no dry streaks remain; overmixing develops gluten and makes the cake rubbery.
-
Scrape the batter into the lined tin and smooth the top. Bake for 28 to 30 minutes, until the center springs back when pressed and a knife inserted in the middle comes out with only a few moist crumbs.
~30 min
The center springs back and moist crumbs indicate the cake is set but still fudgy.
Pull the cake from the oven while the center still looks slightly moist. It firms up as it cools, which keeps the crumb fudgy rather than dry.
-
Cool the cake in the tin for 20 minutes, then lift it out by the parchment and set it on a wire rack to cool completely.
~20 min
Cooling in the tin lets the cake set gradually, preventing it from breaking apart.
-
Grease a knife with 1 tsp butter and cut the cooled cake into 10 equal squares.
~2 min
Greasing the knife reduces sticking, giving clean, even squares.