Cook the onions in the unsalted butter for a couple of minutes until slightly soft and translucent. Place the mashed potatoes, cooed onions, turkey, cabbage and salt and pepper into a bow and mix well. Add the olive oil and a few dry breadcrumbs to form a firm but not stiff mixture. Form into 4 balls and flatten slightly, dust with flour and reserve.
Using a pastry brush,paint egg on both flat sides of the cakes and sprinkle with breadcrumbs, pat down lightly. To finish, heat a couple of tablespoons of vegetable oile in a frying pan and cook the cakes on both sides for 3 minutes.
Place a little watercress on a warm plate. top with a cake, a little more watercress and a poached egg.
This recipe is from Phil Vickery.