Pour the oil into a round Pyrex dish, casserole, or springform tin.
Add your diced sweet potato, sliced courgette, sprigs of thyme, garlic, sea salt, freshly ground black pepper, and mix well.
Roast in the oven for 30 minutes, turning the vegetables over halfway through the cooking time.
In the meantime, whisk together your eggs and creme fraiche in a bowl.
Either crumble your blue cheese (Gorgonzola or Dolcelatte) or grate your hard cheese (such as Comte or Gruyère) or
After 30 minutes in the oven, remove the dish and pour over your eggs and crème fraîche. Top with your cheese of choice, and return to the oven for 25 minutes.
Remove from the oven and leave to cool for 5 minutes.
Serve a good-sized slice alongside a large salad and French dressing.