Place the beef mince into a mixing bowl then add the onion, egg, breadcrumbs, mustard, herbs and seasoning. Mix together with hands until all well combined. Form into four burgers and place in an ovenproof pan or dish.
Preheat the grill to hot, then cook the burgers under the grill for about 15 minutes, turning once, until no longer pink in the centre. Reduce the cooking time if you like your burgers less well done. Remove from the heat and serve in a bun with your favourite toppings.
Try cooking on the BBQ when the family come round!