Dark chocolate cake with white chocolate mousse

I have baked this cake for New Year’s party. My chocolate temptation.
Ingredients
1 cup milk2 cups sugar2 cups plain flour1 cup sunflower oil½ cup cocoa2 eggs1 spoon vanilla essence2 teaspoons bicarbonate soda1 teaspoon salt300 gram good quality white chocolate600 milliliters double cream2 spoons powder gelatin
Cake:
1. Mix together: milk, sugar,