Slice and cube the bread into ½” (1 cm) cubes. You should have about 5-6 cups (1.25 – 1.5 L) of bread cubes. Lay them out in a single layer on a baking tray and let them dry out a little.
Heat the butter and oil, on medium heat, in a large, deep, heavy-based pan. Add the mustard seeds, peppercorns and curry leaves to the pan. Fry together for 30-45 seconds until the mustard seeds start to splutter and curry leaves crisp up a little.
Add the onion and celery to the pan and fry together for 3-4 minutes until they begin to soften.
Add the tomatoes, salt and sugar to the onion mixture. Taste and add a little extra salt, if required. Fry together for about 507 minutes, until the tomatoes are cooked and squidgy.
Tip the bread cubes into the pan and stir together until the bread cubes are coated with the savoury mixture. Take off the heat and let cool.
Gently pour over the broth and stir until the stuffing is well moistened.
Scrape out the stuffing into a butter-greased baking dish. Cover tightly with foil and bake for 25 minutes. Uncover and bake for an additional ten minutes, or until the top is golden and crisp.