Method

• 1.
  Preheat oven to 200°C/180°C fan-forced. Place a baking tray in the oven to preheat.
• 2.
  Line a 26cm x 2.5cm-deep loose-based tart pan with pastry, cutting and pasting sheet to fit and letting excess overhang. Prick base with a fork. Chill for 15 minutes. Line with baking paper and fill with pastry weights. Bake on preheated tray for 15 minutes, then remove weights and paper. Bake for a further 10 minutes until golden.
• 3.
  Meanwhile, heat oil in a large frypan over high heat. Add one-third of the butter and one-third of the mushrooms and cook, stirring occasionally, for 2 minutes, or until golden. Set aside with a slotted spoon and repeat with butter and mushrooms in 2 more batches. Return all mushrooms to pan with garlic and thyme. Season and toss for 2 minutes to soften garlic slightly. Remove from heat.
• 4.
  Whisk eggs and cream in a medium bowl until smooth. Whisk in Gruyere and season with salt flakes and freshly ground black pepper. Using a serrated knife, trim and discard excess pastry. Pour mixture into tart shell and scatter over mushrooms.
• 5.
  Reduce oven to 180°C/160°C fan-forced and bake for 35 minutes, or until set. Remove from oven and stand on a wire rack to cool to room temperature.
• 6.
  Just before serving, season to taste and sprinkle with extra thyme.