1.

Preheat the oven to 300˚F.

2.

Set an ovenproof pot or Dutch oven over medium-high heat, add a drizzle of oil and brown the roast on all sides.

3.

Add the onions to the pan and cook for a few minutes, until starting to brown.

4.

Add the tomatoes, Worcestershire sauce and enough water to almost cover the meat, cover and cook for 3-5 hours, or until the beef is very tender. (Alternatively, cook in a slow cooker on low for 4-8 hours, then transfer the meat to a baking dish.)

5.

Pull the meat apart with forks, stir in the carrot and peas and top with the mashed potatoes, smoothing the top.

6.

Turn the oven up to 375˚F and bake for another 15-20 minutes, until bubbling and golden.