400 g beetroot, scrubbed very clean
1 red onion, finely sliced
300 g block puff pastry
1 egg, lightly beaten
3 tbsp balsamic vinegar
150 feta g, crumbled
1 thyme sprig, leaves stripped, plus more to serve
- Heat the oven to 200C/fan 180C. Trim and quarter the beetroot (wear gloves if you don’t want pink hands) and put the pieces in a roasting tin, drizzle over some olive oil and roast for 30 minutes. Add the onion and roast for a further 20 minutes. Leave to cool a little. Put a flat baking sheet in the oven.
- Roll the pastry out into a large rectangle and score a 1cm border around the edge. Put on another baking sheet and brush the edge with egg. Crosshatch the centre with a sharp knife but don’t cut all the way through. Peel the skin off the beetroot wedges if you like, and cut each piece into 2 or 3. Toss the beetroot in the balsamic and scatter it over the tart, along with the onion, feta and thyme leaves. Season the top well. Put the tart tray on top of the baking sheet and bake for 20-30 minutes or until the pastry is puffed and golden. Push down the center if it has ballooned up. Scatter with more thyme leaves.