- Preheat the oven to 180°C.
- Cut or tear the bread into 1-inch cubes and spread evenly on 2 baking sheets. Toast in the oven until completely dry and beginning to crisp and brown (about 20 minutes). Take out to cool.
- Melt the ghee in a large cast iron skillet over medium to high heat. Add the mushrooms, water chestnuts and a few pinches of salt. Sauté, stirring occasionally, until golden brown (about 6 to 8 minutes).
- Add celery, garlic, onion, sage and thyme. Cook until onions, mushrooms and water chestnuts are sauteed.
- Take off the heat, add the broth and sourdough bread cubes. Season with salt and pepper. Mix gently until all the liquid is absorbed.
- Cover the skillet with foil and cook in the oven at 180°C for 15 minutes. Remove foil and cook for another 20 minutes, or until top is golden. Take out of the oven and let cool for a few minutes.
- Sprinkle with sesame seeds and chopped parsley before serving.