Heat oven to 190C/fan 170C/gas 5.
Beat the butter, sugar, egg, vanilla, zest
and a pinch of salt in a large bowl until
smooth, then fold in the flour and ground
almonds. Shape into 2 rounds, flatten
them, then wrap in cling film and chill
until firm, about 30 mins.
Roll out 1 piece of dough on a floured
surface to about £1 thickness, then
stamp out rounds with a 7cm cutter.
Brush all over with milk, then spoon
20p-size blobs of lemon curd into the
middle of half of the rounds.
Carefully lay the remaining rounds
on top of the lemon curd, then gently
press around the edges with your fingers
to seal. Scatter with a little caster sugar
and the flaked almonds. Bake for 15 mins
until light golden. Repeat with remaining
pastry, then squish any offcuts together
and re-roll. You can freeze the biscuits
before baking, but add up to 5 mins more
to the cooking time.