2 large onions (225g each), halved, thinly sliced
1 tblsp red wine vinegar
1 tblsp brown sugar
2 sheets frozen shortcrust pastry, thawed
250g packet peeled, cooked, whole beetroot, cut into wedges
100g Greek feta, crumbled
1 egg, lightly beaten
Baby spinach and rocket leaves, to serve
Grease a 24cm round, loose-base flan tin. Place on an oven tray.
Heat an oiled, large frying pan over a medium heat. Add onions. Cook, stirring occasionally, for about 8 minutes, or until soft. Stir in vinegar and sugar. Season with salt and pepper. Bring to boil. Boil, stirring, for about 2 minutes, or until liquid has evaporated and onions are caramelised. Remove. Cool.
Place pastry sheets on top of each other at different angles to form a star. Roll out until 40cm in diameter. Lift and press into prepared tin, allowing excess pastry to overhang edge.
Spoon onions evenly over base. Top with beetroot. Sprinkle with feta. Fold excess overhanging pastry over filling to partially cover. Brush egg over pastry.
Cook in a very hot oven (220C) for 15 minutes. Reduce temperature to moderate (180C). Cook for a further 30 to 35 minutes, covering with foil if over-browning, until pastry is golden brown and crisp. Remove from oven. Stand for 5 minutes.
Season tart with salt and pepper. Serve warm with spinach and rocket leaves.