Heat oven to 180C/160C fan/gas 4.
Beat half the sugar and all the butter until
pale, then add whole eggs, one by one,
beating in well each time. Stir in the zest
and a squeeze of lemon juice, then fold in
flour. Check the batter’s consistency; it
should softly drop off the end of a spoon.
Add more lemon juice if it’s a bit stiff.
Line a 12-hole bun tin with cake cases
and put 1 large tbsp mix in each. Smooth
then make a little dip in the centre. Spoon
1 tsp lemon curd into each dip and cover
with 1 tbsp cake mix. Bake for 10 mins.
Meanwhile, place the egg whites into
a clean bowl, whisk until stiff peaks form,
then whisk in the rest of the sugar a tbsp
at a time. Keep whisking until the mixture
looks glossy and has thickened a little,
like shaving foam. Spoon the mixture into
a freezer bag and snip off the end to
leave a hole with a 1.5cm diameter.
Take the cakes out of the oven – tops
should be very pale and just firm – then
pipe meringue all over the cakes. Return
to the oven for 10-15 mins until the cakes
are cooked through and meringue lightly
browned. Can be made 1 day ahead.