Preheat the oven to 200C/180C Fan and place a large non-stick baking tray inside to heat up.
Meanwhile, lightly dust a work surface and rolling pin with flour and unroll the pastry sheet. Roll out until it is slightly thinner and a couple of cm larger than a 23cm (9-inch) loose-based tart tin.
Carefully lift the pastry up and use it to line the tart tin, pressing into the edges. Trim any excess pastry using a sharp knife.
Spread the mincemeat over the base in a smooth and even layer. Pop in the fridge to chill while you make the frangipane.
For the frangipane: in a large bowl, cream together the butter and sugar until pale and fluffy. Gradually beat in the eggs, followed by the ground almonds, until you have a smooth frangipane. Set aside.
Core and slice the apples into half moon shaped and pop into a bowl and squeeze over the lemon juice, making sure all the apple slices are coated.
Spread the frangipane over the chilled mincemeat in a smooth and even layer. Next, starting from the outside, arrange the sliced apples on top, creating a spiral shape.
Carefully place on top of the preheated baking sheet and bake for about 40 minutes - or until the pastry is cooked and the frangipane is golden and firm. Brush with the warm apricot jam, then return to the oven for 5 minutes.
Leave to cool completely before removing from the tin and setting onto a flat plate.
Serve slices cold or slightly warmed with whipped cream.