Heat the oil in a large saucepan over a medium heat. Add the onion, bay leaf, cinnamon sticks and fennel seeds. Cook for about 8-10 minutes, stirring, until the onions are softened and translucent.
Add the ginger and garlic paste, masala curry powder, garam masala and the turmeric and mix well. Add the meat and turn to coat evenly in the onion mixture. Cook for 5 minutes until browned, then add the tomatoes. If the pan looks a little dry add 150 ml of water too.
Simmer over a low heat for 30 minutes, stirring occasionally. Add the potatoes and 100 ml water and continue to cook until the potatoes and the meat are tender. Season to taste.
To assemble cut the bread into quarters ( or if you are using rolls cut off the tops). Hollow out the inners, keeping the crust intact. Scoop the meat and potatoes into the hollow. Garnish with coriander leaves to serve.