Heat the oven to 180C/160C fan/gas 4. Butter two 18cm cake tins and line with baking parchment. Tip the caster sugar in a bowl, then finely zest the lemons into the sugar over the bowl (this ensures the aromatic citrus oils seep into the sugar). Rub the lemon zest into the sugar using your fingertips, then add the butter and beat using an electric whisk for 2-3 mins until the mixture is pale and creamy. Add the eggs, one at a time, beating between each addition, then fold in the flour and baking powder until smooth. Juice half of one of the zested lemons (to give you 2 tbsp) and fold this into the mixture along with just enough of the milk to make a spoonable batter. Divide the batter between the prepared tins and bake for 20-25 mins until golden and risen and the sponge springs back when pressed lightly.

Juice the remaining 1 1/2 lemons into a bowl and stir in the 3 tbsp caster sugar. Brush some of this lemon sugar syrup over the warm sponges in the tins, then leave to cool completely.

When almost ready to serve, put one sponge on a cake stand or serving plate, then drizzle over another spoonful of the lemon syrup. For the cream filling, whip the double cream and icing sugar to soft peaks. Spread the lemon curd over the sponge, then dollop over the whipped cream and smooth it to the edge. Sandwich with the second sponge, flat-side up. Dust with icing sugar and decorate with some pared lemon zest. Will keep chilled for up to three days.