Remove the dairy-free margarine from the refrigerator 30 minutes before starting so it softens.

Press the softened dairy-free margarine across the base of the oven-safe large frying pan using your fingers.

Add the white sugar, salt, and vanilla powder to the pan.

Peel the apples and remove their cores.

Cut the apples into halves or quarters depending on their size.

Pack the apple pieces tightly over the margarine mixture, overlapping them because they shrink while cooking.

Cook the apples over medium-low heat without stirring for 15 to 20 minutes.

Watch until the sugar forms a golden caramel around the apples.

Preheat the oven to 180°C (350°F).

Bake the apples in the frying pan for 20 minutes.

Remove the pan using an oven mitt and unroll the dairy-free puff pastry over the apples.

Tuck the pastry edges inside the pan and prick the pastry several times with a fork.

Bake for a further 30 minutes until the puff pastry is golden and crisp.

Let the tarte cool in the pan for 10 minutes.

Place a serving plate over the pan and carefully invert both together to unmold the tart.

Serve hot, warm, or cold.