Preheat the oven to 338ºF.
In a medium sized bowl, mix the flour, baking soda and salt. Using an electric mixer, mix the oil and sugar at a medium speed until spongy.
Beat the eggs and add the vanilla. Add to the previous mixture until mixed together evenly.
In another bowl, mix the hot water with cocoa powder and coffee powder. Add the cream and milk and bead together.
Mix all the ingredients and pour the mixture into the tin to bake for 20 to 30 minutes or until a knife inserted in it comes out clean.
Leave the cake to cool while we prepare the glaze. To do so, in a bowl mix the chocolate, oil and instant coffee powder. Heat the cream on a medium heat until it boils.
Remove from the heat and pour in the chocolate mixture. Stir until melted and smooth. Add the Kahlúa and vanilla extract. Cool in the refrigerator for 30 minutes.
After this time, stir the glaze again at high speed for 15 to 20 seconds, until the mixture is spongy. Spread the cream over the cake. Leave to cool, and the cake will be ready to serve.