100g golden caster sugar (or 75g caster, 25g dark brown)
20g unsalted butter
200ml whipping cream
Method
Grease and line two standard size cake tins. Preheat the oven to 180C. (N.B baking time will be 20 mins; alternatively use a 22cm loose bottomed or springform cake tin, bake for 30-40 mins, and cut the cake into two layers).
Put the eggs and sugar in a mixing bowl and whisk until the mixture is doubled in size, very pale, and foam like. It should fall off the beaters in a figure of 8 when done. This will take about 10 minutes.
In a separate bowl sift together the baking powder, flour, and cornflour. Gently fold into the egg mixture in small batches. Stir until just combined, trying not to knock out the air.
Spoon the mixture into the prepared cake tins and bake for 20 minutes if using two tins - the cake will be well risen, golden, starting to come away at the edges, and a skewer inserted into the center will come out clean. Leave to rest in the tin for 10 minutes before turning out onto a wire rack to cool.
To assemble, start by making the toffee sauce. Place 200ml whipping cream in a saucepan with 100g sugar. Bring to the boil then turn down the heat and simmer for 10 minutes. Remove from the heat and stir in the butter. Allow to cool (in the fridge is fine).
Sprinkle 1 tbsp milk over each cake half. Spread over the apricot jam. Whip the remaining cream. Spread a layer over the jam and sandwich the cakes. If you have enough cream, mask the outside edges of the cake as well.
Once it is at a pouring consistency, pour the toffee sauce on top of the cake.