Ingredients for the cake
75 grams cocoa powder
1 Tbs instant coffee granules
125 ml hot water
200 grams sour cream
90 ml milk
95 grams unsalted butter
90 ml sunflower oil
260 grams granulated sugar
75 grams soft brown sugar
3 large eggs
1 tsp vanilla extract
300 grams all-purpose flour
1 tsp baking powder
½ tsp baking soda
½ tsp salt
For the chocolate pastry cream
500 ml whole milk
15 grams (1 ½ Tbs) corn flour
115 grams granulated sugar
2 large eggs
1 tsp vanilla extract
20 grams (2 Tbs) cocoa powder
100 grams bittersweet chocolate
60 grams unsalted butter
For the chocolate ganache
250 grams bittersweet chocolate
250 ml cream
Make the cake: Preheat oven to 175 C, fan. Line the base and long sides of a 23 x 33 cm baking pan with greaseproof paper, leaving some hanging from the sides (if baking and serving directly from a glass “Pyrex” pan, no need to line with greaseproof paper but you do need to butter and flour the pan).
Put cocoa powder, instant coffee granules and hot water in a bowl. Whisk until smooth. Add sour cream and milk to the bowl. Whisk again until smooth. Set aside until needed.
In a mixer bowl, whisk together butter and oil. Mixture will not be smooth and that’s ok. Add sugars and whisk again until mixture is light and fluffy.
Add eggs one at a time, whisking well after each addition. Whisk in vanilla extract.
In another bowl, sift together flour, baking powder, baking soda and salt. Add about half of the flour mixture to the mixer bowl. Mix on low speed to combine.
Add the chocolate mixture to the mixer bowl. Mix to combine. Add the remaining flour mixture and mix on low speed until just combined. Don’t over mix.
Transfer cake batter to the prepared pan. Bake for 20-25 minutes until a skewer inserted in the centre comes out with only a few crumbs. Don’t over bake the cake.
Make the chocolate pastry cream while cake bakes. Put the corn flour in a small bowl. Add about 2 Tbs of the milk and stir to dissolve. Set aside.
Put the remaining milk in a saucepan together with half of the sugar. Turn the heat to medium and as soon as mixture starts to heat a little whisk in the cocoa powder. Just as soon as the milk mixture starts to steam a lot (not boil), remove from the heat. Add the chopped chocolate and stir with a spatula until chocolate melts and mixture is smooth.
In a bowl of a stand mixer fitted with the whisk attachment add the eggs, remaining sugar, corn flour mixture and vanilla extract. Beat to combine.
Reduce the speed to medium-low and slowly pour in the warm milk-chocolate mixture while beating constantly. Transfer mixture back to the saucepan and place over medium-low heat. Stir constantly (I like to use a whisk to dissolve any lumps) until cream is thickened and starting to boil.
Remove from heat and whisk in the butter. Whisk until butter has melted and cream is glossy and smooth.
Poke, poke, poke! Take the cake out of the oven. Let it stand for 5 minutes or so. No need to wait for it to cool. Take a wooden spoon and using the handle side, poke holes all over the cake (no mercy!). You can also use the handle of a silicon spatula although the holes will be smaller.
Pour the hot pastry cream all over the cake. Spread the cream to the edges with a spatula and fill in all the holes. Cover cake with plastic wrap. Make sure the plastic wrap is touching the surface of the cream to prevent a skin from forming.
Transfer cake in the fridge for at least 2 hours, preferably longer, to cool completely.
Make the ganache by putting chocolate in a heatproof bowl. Heat cream in a saucepan until just before beginning to boil (cream will steam and bubbles will form). Pour cream over chocolate and let it stand five minutes. Whisk until chocolate has melted and mixture is smooth.
Finish the cake. Take cold cake out of the fridge. Remove plastic wrap and discard. Pour ganache over the entire surface of the cake. Decorate with colorful sprinkles or chocolate shavings for an adult version. Transfer cake back in the fridge until ganache is set.
Use the overhanging paper to remove the cake from the baking pan. If using a glass pan, serve directly from the pan. Slice and serve.
www.cuisinovia.com, Galatia Pamborides