In a bowl, mix 1 1/2 cups flour, the salt and baking soda, cocoa, sugar and vanilla. Add the oil, water with the dissolved coffee in it, the vinegar and mix well. If you feel it's too runny, you can add a little more flour.
Mix it with the nuts or dried fruits of your choice and pour the mixture into an oven dish with baking paper. Put this fast and easy cocoa cake to bake in a preheated 347°F (175 °C) oven for about 30 minutes. Finally, make sure it is ready with a toothpick.
Do not over bake because the longer you cook it, the more crumbly and dry it becomes. Optionally, you can serve it with a glaze or smear it with liquid chocolate.