1. Preheat oven to 180˚C. Place the Beef Wellington on a roasting tray lined with parchment paper.
2. Follow the packaging instructions to cook, and then remove from oven let it rest for 5 minutes. Before cooking you can brush with egg wash to give the pastry an extra golden colour.
3. Peel & cut the potatoes. Add oil & a knob of butter to a pan, then place the peeled potatoes upright in the pan. Add fresh rosemary, season to taste. Cook until golden brown, before adding stock & cover to allow them steam.
4. In a separate pan, melt butter, add the mushrooms, onion, mustard and cook for 90seconds over a medium heat. Add the spinach, cream and season to taste.
5. Remove the beef wellington from the oven and allow 5 minutes to rest. While that is resting, melt butter in a large pan, add the onion and cook for 90 seconds over medium heat, until just softened.
6. Add tenderstem broccoli, add the white wine or stock and season.
7. Sauté for a further 2-3 minutes until the broccoli is cooked through. Remove from the heat and transfer to a serving dish, sprinkling with parsley.
8. Carve the Beef Wellington and serve with broccoli, mushroom medley and potato.