In a large pot add the potatoes and fill with cold water. Add a couple of tablespoons of salt, and bring to a boil. Reduce to simmer and cook for 12-15 minutes or until a fork can pass easily through the potatoes.

Drain the potatoes in a colander. In a mixing bowl using a potato ricer or masher mash the potatoes, stirring in the 4 tablespoons of melted butter and cream. Add salt to taste and set aside.

Preheat the oven to 400F, 200C or gas mark 6.

In a cast iron casserole dish or skillet on, medium-high heat, cook the ground beef or lamb until browned, remove from the heat and place into a bowl. Return the casserole pan or skillet back to the heat.

Add the remaining butter and cook the onions, celery and carrots until soft, about 5-7 minutes. Add the red wine, beef broth and cooked lamb or beef. Cook until the liquid has reduced. Add the tomato paste and Worcestershire sauce.

Remove from the heat and add the peas. Pour into an oven save casserole dish if desired.

Using a spoon or spatula spread the mashed potatoes on top and bake for 40-45 minutes or until the potatoes have turned golden brown.