METHOD

THE FILLING

1. Preheat the oven to 160Cº.
2. Place the minced beef into a large mixing bowl and loosen and break apart. Season with salt and pepper. 
3. Place a large, casserole pan over a high heat with a lug of olive oil. Add loose handfuls of the minced beef into the pan browning the mince for about 2-3 minutes. You will almost certainly need to do this in batches. Once the meat is browned remove from the pan. 
4. Add in the onion, carrot and celery into the pan and cook for 3-4 minutes until starting to colour. Add the garlic and cook for a further 2 minutes. Add the flour and butter into the pan and mix together, until the butter has melted and the flour coats the vegetables. 
5. Deglaze the pan with a splash of the red wine, scraping off any fond at the bottom of the pan, before adding the tomato concentrate to the pan and cooking out for 2 minutes. 
6. Return the meat to the pan and add the wine. Increase the heat to the pan and allow the wine to reduce by half, stirring occasionally to prevent anything catching on the bottom of the pan. 
7. Once the wine is reduced, add the worcester sauce and the beef stock into the pan and bring to a gentle simmer. Add the thyme and bay leaves and transfer the dish to the oven with a lid. Cook for 1½ hours until the meat is very tender and the liquid has reduced almost entirely. You want the filling not to be too wet and capable of holding its own shape.

THE BONE MARROW MASH

1. Peel the potatoes and dice into eighths. Add to a pan of cold, salted water and bring to the boil, reduce the heat and simmer for 15-25 minutes until easily pierced by a fork.
2. Preheat the oven to 180ºC (Fan).
3. Place the halved bones onto a baking tray and season the bone marrow heavily with salt and pepper. Lay a branch or two of rosemary over the bone marrow and place into the oven.
4. Bake in the oven for 10-20 minutes depending on the bone marrow thickness. The bone marrow should be starting to melt a bubbling around the edges slightly, but not sliding out of the bones.
5. Drain the potatoes and then puree with a hand masher or potato ricer.
6. Then, using a whisk, beat in the milk until loosened and finally fold in the cooked bone marrow and egg yolks.

ASSEMBLING THE COTTAGE PIE

1. Add the filling to a large pie dish. To finish, top with the bone marrow mash and score a design of your choosing into the mash. 

TIP – The Cottage Pie can be assembled a day in advance if necessary and will freeze extremely well too.

2. Preheat the oven to 180Cº.
3. Place the pie in the oven and bake for 30-40 minutes until the mashed potato has turned golden brown and crisp.
4. Remove from the oven and allow to sit for 5 minutes before serving.