When making every day cakes I don't always like to add a topping, instead I like to put all the extra flavours and textures inside the cake instead, especially if I am busy (this cake took less than 45 minutes from ingredients to serving in total) it's just easier doing everything in one go plus my kids are little monkeys who like to only eat the toppings some days!
I don't often bake for myself but I really fancied a chocolate cake so made this gluten free, I also fancied extra flavours, moisture and bite so added cream cheese (I used Philadelphia) and a sprinkle of sugar on top. I was so looking forward to eating this cake, I didn't wait for it to cool before having some! It might not look like the most amazing cake ever but it tasted so good!
Of course you can add more or less cream cheese to your taste, you can even replace it for peanut butter or nutella if you wanted.
Also please use butter, not margarine.