Preheat the oven to 450°F (230°C). Put the vegetables into a roasting pan, drizzle the olive oil over them, sprinkle with freshly ground black pepper and toss together. Roast the vegetables for 30 minutes until browned. Remove and leave to cool. Reduce the oven to 350°F (180°C). Put a baking tray into the oven.
Meanwhile, to make the pastry, combine the flour, sesame seeds and a pinch of salt in a bowl, then rub in the spread with your fingertips. When the mixture resembles breadcrumbs, stir in the cold water, or as much as is needed, with a round-bladed knife, to form the mixture into a soft dough. Wrap with plastic wrap and chill for 15-20 minutes.
Unwrap the pastry and roll out on a floured work surface to a circle about 25 cm round. Lift it over a 21 cm flan pan and gently press the pastry onto the base and sides. Trim off the excess.
In a wide pitcher or bowl, combine the eggs with the milk and cheese. Season with the chili flakes or pepper.Spoon the roasted vegetables into the pastry case, mounding them in the centre, then pour over the cheesy egg custard.
Set the pan on the heated baking tray and bake for 25 minutes until just set, puffed and golden. Remove from the oven and leave to stand for 5 minutes before serving. Eat warm from the oven or at room temperature.
Per serving: 519 calories, 27 g fat (6.5 g saturated), 18.5 g protein, 46 g carbohydrate, 8 g fibre