Combine cocoa together with instant coffee. Stir in warm water; mix to dissolve, until smooth.
Whisk egg yolks with sugar until it's smooth. Add vegetable oil to the mix.
Gradually stir in a mixture of cocoa-coffee.
Combine flour together with baking powder and soda. In thirds, mix into a bowl with the dough. Stir the flour into the dough, until it’s completely mixed.
To the bowl of whites, add salt. Beat until whites look like foam, and if you were to flip the bowl upside-down, they would not fall out.
Very carefully, mix in - beaten egg whites into the batter. Especially, carefully mix first portion of the whites, because whites and the dough have very different textures, which gradually will become one. Mix whites into dough by folding movements, top - down.
Pour the batter into the pan and bake in a preheated 300F oven, for about 50 minutes. Use a wooden toothpick to check if the dough is baked.
In the process of baking, especially in the first 30 minutes, do not open the oven door! Otherwise, there is a high probability that the cake will settle.
Remove the cake from the oven. Let the cake cool to a room temperature, then slice it into 4 layers. Soak the cake with sweetened whipping cream.