Roll pastry on well-floured board into 30 cm circle. Brush off any excess flour. Transfer to 23 cm pie pan; trim to 1 cm overhang. Crimp to form stand-up edge. Prick bottom of dough all over with fork. Refrigerate at least 30 minutes.
Heat oven to 450. Line dough with aluminum foil; fill with dried beans or pie weights. Bake for 10 minutes. Reduce oven temperature to 350. Bake for 10 minutes more. Remove foil and beans. Bake until crust is golden, about 15 minutes. Cool on rack.
Heat butter in large skillet. Add apples and sugar; cook, stirring, until apples are very tender and thickely glazed, 15-20 minutes. Cool to room temperature.
Heat milk in saucepan until bubbles appear around edge of pan. Whisk yolk, syrup, cornstarch and vanilla in bowl until smooth. Gradually whisk in milk. Return mixture to saucepan. Stir over low heat until thickened. Remove saucepan from heat; whisk for 1 minute.
Spoon apples into crust. Top with hot maple mixture; smooth top. Cool to room temperature. Refrigerate until custard is firm, about 1hour. Beat cream in bowl until soft peaks form. Beat in sugar and cinnamon until firm peaks form. To serve, decorate with whipped cream.