Saffron paella

Preheat the oven to 200ºC.
Melt the butter in a 30cm paella pan or a large oven-proof sauté pan. Add the onion, celery, garlic and salt and cook until the onion is tender. Stir in the thyme, saffron and rice, coating it well in the butter. Pour in the hot stock, stir and bring to the boil. Simmer for 5 minutes then cover with tin foil and place in the oven to cook
for 15 minutes.

Remove from the oven and rest, still covered, for 5 minutes before serving. Gently fluff up with a fork.