- 6 decent-sized onions, halved and peeled
- 50g butter
- 1 tbsp brown sugar
- 2 tbsp balsamic vinegar
- Sea salt and freshly ground pepper
- A few sprigs of thyme (after thyme)
- A batch of homemade, all-butter puffish pastry (see our website), or 250g puff pastry
Prep: 15 mins | Cook: 40 mins
1. Heat your oven to 180°C/Fan 160°C/Gas 6.
2. Cut the onions lengthways (from root to stem) into wedges.
3. Melt the butter in a 20cm ovenproof frying pan. Swirl in the sugar, till dissolved.
4. Add the onions and fry them over a medium heat, turning them now and again, till just beginning to brown.
5. Trickle over the vinegar and cook till it’s reduced down to a sticky glaze. Gently shake the pan occasionally so the onions don’t stick. Arrange the onions evenly – or into a nice pattern (it’ll be the top of the tart later).
6. Scatter over a few thyme leaves and season with a pinch of salt and pepper. Take the pan off the heat and leave it to cool while you prepare the pastry.
7. Roll out the pastry on a lightly floured surface. Cut it into a circle slightly larger than the pan. Lay the pastry over the onions, tucking it down the sides of the pan. Make 2 small slits in the centre for the steam to escape while cooking.
8. Slide into the oven and bake for 25-30 mins, or till the pastry is golden and crisp. Let the tart stand int the pan for a few mins. To turn the tart out, pop a plate face-down over the top of the pan, then use oven mitts to flip the tart onto the plate.
9. Finish with a few fresh thyme leaves and a little more salt and pepper. This tart is delicious served hot or cold.