Beat the butter and sugar together then whisk with the syrup, vanilla and custard powder until pale and fluffy. Sandwich the biscuits with the filling. Place the teabags, zest of lemon ...
Pour over the chilled crust and spread evenly. Allow to cool in the fridge until set, about 2 hours. Mix the condensed milk and lemon juice and spread over the set custard filling. Spoon the ...