Double chocolate malt cake

Double Chocolate Malt Cake - The most requested birthday cake in my family.
Talking about a one-tracked mind. I have been baking this chocolate malt cake 3 times a year for the last 6 years as a request from all 3 children for a birthday cake. It is that good but it is not for a calorie-controlled folks like me.
The original recipe is from a self-taught food writer, Felicity Cloake. Malted milk powder (I use Horlicks) gives the icing a light-yellow colour with a mellow nutty flavour and a natural sweetness. In the cake, there are malted milk powder, Belgian dark chocolate, light brown sugar and some cocoa powder. To finish off, top the cake with crushed Oreos and Maltesers!!!… you can imagine the intensity of the taste. If it was a wine, it is certainly not a Pinot Noir but a full-bodied Barolo!!
Ingredients
50g Belgian dark chocolate
250g butter, softened
250g soft, light brown sugar
100g cocoa powder
150g malted milk powder ( I used Horlicks )
100g plain flour
3 tsp baking powder
3 medium eggs, beaten
250 ml milk
For the decoration
150g butter, softend
50g malted milk powder
200g icing sugar
4tbsp milk
10 Oreo biscuits
a handful of Maltesers
Method
Heat the oven to 200c , fan 180c. Grease and line 2*20 cm cake tins.
Melt the chocolate in the microwave in medium heat for about 3 minutes stir every minute until compleately melted.
Cream together butter, sugar and salt using an electric mixer until fluffy.
In another bowl sift together all the dry ingredients.
While the mixer still running, add the eggs to the butter and sugar. Once combined, fold in half of the dry ingredients, the melted chocolate, then the rest of the dry ingredients. Slowly add the milk until the mixture drops easily from a spoon. ( you might not need all of the milk)
Divide the mixture between the 2 tins. I weight it out to make sure they are even. Bake for 25-30 minutes, until firm in the middle. Cool for 10 minutes in the tins, then turn out onto a wire rack. The cake will sink a bit in the middle as the malt powder milk powder is a heavy ingredient.
To make the icing, beat the butter until very soft then add in the malted milk powder, icing sugar and a pinch of salt, followed by the milk to loosen up the mixture,
Once the cakes are completely cool, put the less flat one on a serving plate and spread with a third of the icing. Top with the other cake and spread the remaining icing on top.
Crush the biscuits in a plactic bag with a rolling pin. Then sprinkle on top. Finish with the Maltesers, lightly crushed.