Method

• 1.
  Preheat oven to 220°C/200°C fan-forced.
• 2.
  Melt half the butter in a 22cm heavy-based, ovenproof frypan over medium-high heat. Add the eschalot and thyme sprigs, and cook for 2-3 minutes on each side until golden and starting to soften. Set eschalot aside. Melt remaining butter in same pan and cook cauliflower, in batches, for 2-3 minutes each side until golden. Set cauliflower aside. Discard thyme sprigs.
• 3.
  Wipe pan clean and return to high heat. Add sugar to hot pan and cook for 2-3 minutes until caramelised. Stir in lemon juice until combined. Remove from heat. Arrange cauliflower and eschalot, cut-side down, in pan.
• 4.
  Trim pastry into a circle a little larger than the pan and place over vegetables, tucking the edges into side of pan. Bake for 25 minutes. Reduce oven to 180°C/160°C fan-forced and bake for a further 10 minutes or until pastry is golden brown and flaky.
• 5.
  Remove from oven and stand for 5-10 minutes. Run a knife around edge of pan to loosen pastry from the side, and carefully turn tarte out onto a large serving plate or chopping board.
• 6.
  Serve sprinkled with cheese, walnuts and extra thyme leaves, and seasoned with freshly ground black pepper.