Preheat the oven to 170°C by turning it up and down.
In a large bowl, beat the eggs together with the sugar and beat with a whisk until you get a foamy mixture that is slightly whitish and has increased in volume. Some medium to high speed electric wands will make your job a lot easier.
Then add the sunflower oil drop by drop, little by little, while continuing to beat until fully incorporated.
Then add the milk little by little and stir until a homogeneous mass is formed.
In another bowl, mix the remaining solid ingredients, i.e. flour, cocoa, yeast and salt.
Now gradually add these ingredients in tablespoons to the previous dough, beating with the whisk, but now at low speed. Do this until you get a homogeneous mass without lumps.
Grease a cake tin very well on all sides with butter and then use a sieve to sprinkle a thin layer of flour over the butter. Stir the flour very well so that it is distributed throughout the mold. Then turn the mold over and tap it a few times to remove the excess. This way you can easily remove your cake from the pan once it's ready. You can see this technique step by step in the article “How to properly unmold a cake”.
Pour the dough into the mold, spreading it well throughout and tapping the mold on the work surface a few times (lightly) so that it is well balanced.
Bake the cake for 50 minutes at 170 °C, heating up and down. After this time, pierce it with a skewer to see if it is completely cooked. If it comes out dry, it's perfect.
Once it's ready, take it out of the oven and leave it on a rack for 10 to 15