- 320 g puff pastry
- 800 g (1lb 12oz) medium-sized red onions
- 25 g (1oz) butter
- 1 tbsp. extra virgin Greek olive oil
- 1 tsp. sugar
- 2 teaspoons dried Greek wild thyme plus extra to garnish
- 100 ml (3 ½ fl oz) Mavrodaphne wine or other sweet red wine such as port
- 2 tablespoons petimezi
- 1 tablespoon Greek balsamic vinegar
- 1 garlic clove crushed
- Unroll the pastry and cut out a circle 1cm (½ in) larger in diameter than the rim of your frying pan. Transfer pastry to a baking sheet and chill until needed. Preheat oven to 190°C (170°C convection) or 375F.
- Peel and cut onions into equal size wedges through the root (this will help keep layers together).
- Melt butter, oil and sugar in the frying pan. Remove pan from heat and arrange onions in concentric circles, with a cut side down. Return pan to medium heat and cook for 10-12min until onions begin to caramelise on the underside (try not to disturb wedges or they’ll lose their shape).
- Add thyme, port, petimezi, garlic, and generous salt. Cook and let the onions bubble for 3 to 5 minutes, until pan juices start to thicken, then remove from heat and cool for 10min.
- Carefully cover onions with the pastry circle, tucking pastry down into the sides. Make a few small slits in the pastry with a sharp knife to allow steam to escape.
- Put pan into the oven for 20-25 min or until pastry is puffed and golden.
- While the tart is baking, whip together all the ingredients for the feta-mastiha cream in a food processor and set aside in the fridge to firm up.
- Remove the tart and let it rest at room temperature for 5 minutes, then carefully invert on to a board or plate. Garnish with more thyme, if you like, and serve hot or at room temperature, garnished with a dollop of the mastiha-feta cream.