Thinly slice onions, add to pan with oil and butter and cook for 12 to 15 minutes stirring frequently

Add sugar, red wine vinegar and a pinch of salt and continue to cook for a further 15 - 20 minutes or until consistency resembles marmalade

Whilst onions are cooking line 9 inch tart dish with pastry leaving an inch over hanging around the edge, (make small slices/air holes in base to avoid a mountain pie!). Chop feta cheese into small blocks and place around the edge of the pie and fold over the pastry - Stuffed crust!

Spread the caramelised onion in the centre of the pie. Thinly slice tomatoes and evenly cover the onion spread. Cook in the oven for 20~25 minutes or until pastry is a golden colour.