To make the pastry, rub the butter into the plain flour. Add the eggs and mix until a dough forms. Wrap it in cling film and chill in the fridge for 30 minutes
Pre-heat your oven to 160C Fan/180C/350F/Gas Mark 4
Roll the pastry out onto some cling film, then line a 28cm diameter loose bottomed tart tin with it
Line the pastry with baking paper, then add baking beans and bake for 15 mins
Remove the baking beans and baking paper, put the pastry back in the oven for another 10 minutes until fully cooked on the bottom
Cut the plums into thin wedges and arrange them in the pastry base
Make the custard by whisking together the zest and juice of the lemons, the double cream, the ground almonds, the melted butter, the eggs and the golden caster sugar. Whisk it well, then gently stir in the limoncello
Place the pastry with the arranged plums in onto the oven shelf, then pour the custard in. Bake it for 25 minutes until the custard is set, but still has a slight wobble
Once it is cooled fully, dust it with icing sugar