First of all, you have to preheat your oven to 350 degrees Fahrenheit i.e. 175 degrees Centigrade. Take a loaf pan and grease it with the help of oil or butter.
Then, take a bowl and add the sugar, flour, cocoa, baking soda and salt in it. Mix all the ingredients well with each other with the help of a fork. After that, add the vanilla extract, distilled vinegar, oil and water. Mix the ingredients again until they get smooth.
After mixing all the ingredients well with each, you have to pour the mixture into the baking pan which you prepared in the first step.
Place the pan in the oven and bake the mixture for around 45 minutes (until the mixture becomes golden brown). Take the pan out of the oven and keep it aside so that it may cool down.
In order to check whether the cake is ready or not, you can insert a toothpick in it. If the toothpick comes out clean, it means your cake is ready. But, if the toothpick comes out with some particles of the mixture, it means you have to bake it for few more minutes.
Serve the cake along with some chocolate sauce and enjoy the birthday party at your home.