Preheat the oven to 180°C, fan 160°C, gas 4.
In a medium bowl, cream together the butter and sugar until pale and fluffy. Mix in one whole egg and one egg yolk until combined (save the egg white for another recipe). Gently fold in the ground almonds and flour until combined.
Spread the frangipane mixture over the base of the pastry case. Top with the sliced apple and brush all over with the apricot jam.
Bake in the oven for 1 hour.
Cook's tip: always make sure your butter is at room temperature but don't be tempted to use the microwave to bring it to the right temperature. The micrwave can create patches of melted butter and this will affect the finished dessert.