Caramelised Onion & Gruyère Tarte Tatin

• 1egg, beaten, for glazing
• Fine salt, to taste
• 6small to medium onions (about 600 g), peeled and halved through the root
• 1 tspfresh thyme leaves
• 2 tbspbalsamic vinegar
• 1 tbspsoft brown sugar
• 50 gbutter
• 2 tbspolive oil
• 1 x 320gsheet ready-rolled puff pastry
• 120 gvegetarian Gruyère-style cheese, coarsely grated
• Black pepper, to taste

Method

1. 1Heat the oven to 200°C/180°C fan. Melt the butter with the olive oil over medium-low heat in a 28 cm ovenproof frying pan. Check that your pastry sheet can cover the pan, rolling it a little wider if needed.
2. 2Season the onions and arrange cut-side down in one snug layer. Cover and cook for 10 minutes to soften the centres.
3. 3Uncover and cook for another 20 minutes, checking the heat occasionally, until the cut sides are deeply golden and the onions are nearly tender. Lower the heat if they darken before softening.
4. 4Splash in the balsamic vinegar; it'll hiss and lift all the sticky bits off the pan, which is exactly what you want. Scatter over the brown sugar and thyme leaves. Cook for another 5 minutes, swirling the pan occasionally, until the liquid turns syrupy and clings to the onions like a glaze.
5. 5Slide off the heat and let everything settle for a couple of minutes. Scatter the Gruyère generously between and over the onions, letting it tumble into every gap and pool against the hot pan.
6. 6Drape the puff pastry over the top, tucking the edges down inside the pan around the onions like a duvet; that tucked edge becomes the crisp rim once you flip it. Brush lightly with the beaten egg; discard any leftover glaze.
7. 7Bake for 25–30 minutes, until the pastry is deeply golden, puffed and properly crisp. Pale pastry will go soggy under the onions; give it the full colour. Rest for 5 minutes; this is important, or the caramel will run when you flip.
8. 8Place a large serving plate over the pan, and with a confident movement (and oven gloves), invert the whole thing. Lift the pan away to reveal the glossy onions on top.

Per serving

kcal

451

protein

11.6g

fibre

2.5g

carbs

32.1g

fat

31.3g