Preheat the oven to 190 C / Gas 5. Grease a baking dish.
Soak the saffron in the warmed chicken stock for 10 minutes.
Slice the potatoes thinly, but do not cut all the way through, just enough to fan them out yet maintain their form. (Tip: Lay two chopsticks on either side of the potato and slice; the chopsticks will prevent cutting all the way through.)
Arrange the potatoes in the prepared baking dish and drizzle with olive oil and dot with butter. Sprinkle with the garlic, thyme and seasoning. Pour the saffron stock into the dish with the potatoes.
Bake for 1 hour in the preheated oven until tender and most of the liquid has been absorbed by the potatoes.
For vegetarian diets, substitute the chicken stock for vegetable stock.