Place a large oven tray in the oven; preheat the oven to 200°C.
1. Grease an 11cm x 34cm rectangular loose-based tart tin. Place sheets of pastry, end to end, overlapping by 3mm, on a work surface. Using the tip of a knife, press overlaps slightly to join the pastry. Cut 5cm from the length of the pastry and discard the trimming. Lift the pastry into the tin; ease into the base and sides, trim excess pastry 3mm beyond the edge. Freeze for 10 minutes.
2. Frangipane Process the butter, sugar, eggs and almonds until combined. Add flour, then process briefly until mixture is combined.