Keep an eye on the temperature, moving the pan off the heat briefly if needed. Add the egg yolks and whisk vigorously – they mustn't curdle! Keep whisking until thickened, roughly the consistency of custard.

Remove from the heat and let it cool, stirring from time to time so a skin doesn't form on top.

Put room-temperature butter into a bowl and whip it for about 5-10 minutes, until you get a beautifully light, almost white, fluffy texture.

Gradually beat the cooled yolk-and-cream mixture into the whipped butter until fully combined, then place the cream in the fridge to firm up – this takes about 2 hours.

Put the sugar into a small saucepan and drizzle in a little water – don't stir. Heat until the sugar starts to caramelise, then add the almond flakes. 'Toast' them this way until golden brown.

Tip the almonds onto baking paper to cool and dry. Once dry (they'll no longer feel sticky from the caramel), put them in a chopper and grind finely. Your brittle is ready.

The cooled sponge should be about 4 cm tall (using a 21 cm tin). Carefully slice it in half to get two thin layers.

Spread cream over the first layer and sprinkle with the almond brittle. Spread cream on the second layer too, including the side that will touch the brittle, then press the two layers together.

Spread cream over the top and sides of the cake – this is easiest when the cream is firmer straight from the fridge. If the cream starts to soften, pop it back in the fridge for about 10 minutes and continue once it's firmer again. Once finished, chill the whole cake until fully set.

Decorate the top of the cake with toasted almond flakes or almond brittle – I used both.