Preheat the oven to 180 degrees Celsius (350 Fahrenheit),
To make the sponge, add the eggs and sugar to a large mixing bowl, and use a hand mixer to beat them together until the mixture doubles its volume.
Sift in the flour, add the baking powder, spices, chopped pistachios, oil and grated carrots (squeeze the liquid well).
Use a spatula to combine all the ingredients into a uniform batter.
Line a large baking tray with non-stick paper, transfer the batter and spread it in one even layer.
Bake for 30 minutes.
Remove the tray from the oven and allow the cake to cool down completely.
To make the frosting, add the butter, cream cheese and vanilla extract to a large mixing bowl, and use a hand mixer to cream them well.
Sift in the icing sugar, and beat again to a silky texture.
Top the cooled sponge with the frosting, and decorate with the sprinkles and chocolates.