1. Heat the oil in a large, deep pan. Fry the fennel pieces and potato on each side until well caramelised. Add the garlic, orange zest and thyme and season well with salt and pepper.
2. Now add the milk, butter and fennel seeds and bring to the boil. Turn down and cover with a cartouche. Cook for 25-30 minutes or until the potatoes are tender, check half way through cooking, if the dish requires more liquid add a little more milk.
3. Option: once cooked transfer the fennel to a baking dish and sprinkle with parmesan. Grill for a minute under a grill until golden brown.