Preheat the oven to 350°F. Peel the apples, remove the cores, and slice them into rounds.

Melt the salted butter in a large pan, add the superfine sugar and water, and bring to a boil over medium heat until you have a golden, syrupy caramel. Add the apple slices and let them soften briefly, stirring occasionally.

Arrange the apple slices tightly together in a deep tart tin or loaf pan, with the rounded side facing down. Pour the caramel over them and place the shortcrust pastry on top, pressing the edges around the apples and against the tin.

Bake the tart until done in the oven until the pastry is golden brown. Place a plate on top of the tin, hold everything firmly together, and invert the tart in one go.

Serve the tart warm or lukewarm, optionally with vanilla ice cream or thick fresh cream.