Brush the cake pan with oil and dust it with all-purpose flour. At the bottom put a butter paper/ parchment paper.
In a bowl sift in the al-purpose flour, cocoa powder, baking soda, salt and sugar. Sift it twice for all ingredients to combine well.
Now add oil and vanilla extract to the dry ingredients.
In a glass or small bowl take warm water and add expresso powder if you are using it in the cake, followed by vinegar. Mix it all together and add it to the dry ingredients.
Whisk it all together till it turns into a smooth batter without any lumps.
Pour the batter in a 8 inch pan and tap it on the work surface couple of times to remove any uneven bubbles.
Bake it in the pre-heated oven for 40-45 minutes. Since each oven has different heating check if the cake is done at 40 mins by inserting a toothpick and if needed then continue to bake till the toothpick comes clean.
Let the cake cool down for about 30 minutes before taking it out of the pan. If you take it out before cooling the cake could break.
After its cooled completely run a knife along the edge to release the cake and the flip it over a wire rack and transfer it to a plate.
Enjoy the rich, delicious and moist eggless chocolate cake.
Notes
Do not over mix the batter, just mix it till all ingredients mix well together.
Pre-heat the oven before you start making the batter so that the batter does not need to rest for too long after mixing.
Adding espresso coffee enhances the flavor but it is not a compulsory ingredient for this cake.
Test the baking soda before using it, if it's not fresh then the cake will not rise.
Use cooking vinegar only. Be careful not to use cleaning vinegar.
Do not forget to grease and flour the cake pan.
Use flavorless oil to get the best results.
Let the cake cool completely before taking it out of the pan.
If you are using a 6-inch pan, use 2 pans and bake it for 30-32 minutes.