In a large bowl add the beef mince, egg, breadcrumbs, Worcestershire sauce, salt & pepper. Mix well with your hands, then shape into 4 even patties

In a large fry pan, heat 1 tbsp oil until hot. Add patties and cook for 2 minutes until golden. Flip carefully, cook for another 2 minutes. Transfer to a plate to rest

Meanwhile in a small bowl, mash the avocado with the juice of 1/2 a lemon

Set your oven grill to 180 degrees. Cut the rolls in half and place on a lined tray. Toast the rolls for a few minutes under the grill, until golden & crunchy

To assemble your burger, place the bottom half of your roll on a plate, spread with a tbsp of mashed avocado, slice of tomato, slice of beetroot, beef patty, more mashed avocado and then crumble some feta on top, add some pickled red onions and the top of your roll. Serve immediately