Preheat your oven to 400°F (200°C).

Unroll the pastry and line a 9-inch tart pan with it, trimming any excess edges. Prick the base with a fork.

Spread the salted caramel sauce evenly over the bottom of the pastry shell.

In a mixing bowl, cream together the softened butter and sugar until pale and fluffy.

Beat in the egg and vanilla extract, then fold in the ground hazelnuts and flour until a smooth frangipane forms.

Spread the hazelnut frangipane gently over the caramel layer.

Arrange the apple slices in a concentric circular pattern on top of the frangipane, pressing them down slightly.

Bake for 35-40 minutes, or until the pastry is golden brown and the frangipane is set and puffed.

While warm, heat the apricot jam with a teaspoon of water and brush it over the apples for a glossy finish.

Allow the tart to cool slightly before slicing and serving.