Birthday Custard Sponge by Nigella Lawson

I made Peach Cream Pie last year that required instant vanilla mix pudding. However, I was unable to find it in our local supermarket, I substituted it with custard powder. The cream and peach filling came out delicious, however the crust (where the vanilla mix pudding was required) didn't come out as soft as I imagined it to be. I'll try to post a more successful trial in the coming months.

Meanwhile, I was left with a tin of custard powder. Not wanting it to go to waste, I search the internet for recipes that would require custard powder. One recipe that picked my curiousity was Nigella Lawson's Birthday Custard Sponge. It was timely as my Mama's birthday was coming up. So i decided to give it a try.

The sponge came out dense. The buttercream filling for me lacked flavor. Despite having the ingredients sifted and mixing the buttercream well, it had the unmelted confectioner's sugar feel to it. Please share tips to solve this problem. I used unsweetened chocolate for the icing, which perfectly offsetted the sweetness of the dense cake. My family commented it was a "different" cake from what we are used to. As they said, "good but different. "

Ingredients

For the sponge
1.5 cups or 200 gram(s) plain flour
3 tablespoon(s) custard powder
2 teaspoon(s) baking powder
½ teaspoon(s) bicarbonate of soda
4 medium egg(s)
1 cup or 225 gram(s) butter (soft)
1 cup or 200 gram(s) caster sugar
2.5 tablespoon(s) milk

For the buttercream filling
1 cup or 125 gram(s) icing sugar
4 teaspoon(s) custard powder
2/3 cup or 75 gram(s) unsalted butter (soft)
1.5 teaspoon(s) boiling water (from recently boiled kettle)

For the chocolate icing
60 ml water
2 tablespoon(s) golden syrup
2/3 cup or 125 gram(s) caster sugar (or use 50g if using milk chocolate)
175 gram(s) dark chocolate
1 packet(s) hundreds and thousands

1. FOR THE SPONGE: Make sure everything you need is at room temperature before you start. Preheat the oven to gas mark 180°C, and butter and line two 20cm (8-inch) round pans.
2. Put all of the above ingredients except the milk, into a food processor. Process to a smooth batter, and then add the milk a tablespoon at a time to make a soft dropping consistency.
3. Divide between the two cake tins and bake for 20 minutes. The cakes will have risen and feel spookily puffy; this is because of the cornflour in the custard powder.
4. Let the tins sit on a cooling rack for 5 minutes and then turn them out on to the rack, peeling away the paper.
5. FOR THE BUTTERCREAM ICING: Process the icing sugar and custard powder to get rid of any lumps (I even sifted them together), and then add the butter, processing again to make the buttercream come together. Feed the boiling water down the funnel with the motor running to make the filling easier to spread. Then sandwich the cooled sponges together with the custardy buttercream.
6. FOR THE CHOCOLATE ICING: Combine the water, syrup and sugar in a saucepan, stirring to dissolve over a low heat. Let it come to the boil and then take it off the heat.
7. Break up the chocolate into small pieces and then add to the pan, swirling it around to cover in the hot liquid. Leave to melt for a few minutes, and then whisk the icing to make it smooth and shiny. Pour over the buttercream filled cake, letting it drip down the sides, and then sprinkle generously with the hundreds and thousands before the icing sets.