Ingredients 2 tbsp mustard powder 1 tbsp sea salt 2 tsp brown sugar 1 tbsp sunflower or light olive oil 1.2 kg British grass-fed topside of beef Gravy 150 ml madeira, red wine or port 2 tbsp plain flour 500 ml beef stock Method Heat the oven to 220°C/200°C fan. Put the mustard powder, salt,…