Method

1. Place the vegetables in a large pan and add enough water to cover, season with salt and bring to the boil. Allow to simmer for 4–5 minutes, then quickly drain the vegetables and refresh in a bowl of iced water (this halts the cooking process and helps to retain their colours).
2. Drain the cooled vegetables and leave to dry on some kitchen towel
3. Preheat the oven to 200°C/gas mark 6
4. Roll out the puff pastry on a lightly floured surface. Using an ovenproof frying pan (approx. 25cm) as your guide, trim the pastry to a circle that is slightly bigger than the pan. Transfer to a baking tray lined with baking parchment and chill in the fridge
5. Place the frying pan on a medium-high heat and add the butter, vinegar and sugar, stirring until melted together. Reduce the heat slightly, and add the shallots – try to keep the rings intact by not moving them too much
6. Once they begin to soften and caramelise, scatter over the thyme leaves, shaking the pan gently to combine. Remove the pan from the heat and allow to cool for 5 minutes
7. Place the par-boiled vegetable rounds in a decorative pattern across the base of the pan, arranged like a mosaic with a mix of large and small pieces to fill the gaps. Make sure all the vegetables are coated in the butter glaze
8. Remove the pastry circle form the fridge and place on top of the vegetables in the pan. Gently tuck the edges in around the vegetables
9. Transfer the pan to the oven and bake for 20 minutes, then check the tarte to see if there is any excess butter or liquid bubbling up around the sides – if so, gently pour this away (you may need to use kitchen towel or a cloth to hold the tarte in place)
10. Reduce the oven to 180°C/gas mark 4 and return the tarte to the oven for a further 15–20 minutes, until the pastry has risen and is golden brown
11. Leave to cool for 10 minutes (the pastry will deflate slightly in this time), then place a plate over the top of the pan and carefully flip the pan over, so the tarte Tatin turns out on to the plate. Serve the tarte warm, perhaps with a fresh salad