Preheat your oven to 180’C
Fry the onion in a deep pan with the olive oil until soft.
Add the carrot and the beef and then fry until the beef has turned brown.
Add the garlic, Worcester sauce and herbs and fry for another 2 minutes until the Worcester sauce has pretty much been absorbed.
Pour in the stock, marmite, gravy granules and puree and leave to simmer for 30-40 minutes until thick and rich and then stir in the peas just as you turn off the heat.
In the meantime boil the potatoes in salty water for 20minutes until soft.
Remove from the heat, drain and then return to the heat to sweat off the excess water.
Mash with the butter, horseradish and salt and pepper. Return the mashed potato to a low heat and beat with a wooden spoon until smooth and fluffy.
Fill an oven proof dish with the meat mixture, then top with the mashed potato and sprinkle with grated cheese.
Bake in the oven for 40minutes until the top it lovely and crispy.