Preheat the grill to medium.
For the burger, place the chopped steak, breadcrumbs, Tabasco, salt and freshly ground black pepper and egg yolk into a mini blender and pulse until coarsely chopped. Shape into a patty using your hands.
Heat the olive oil in a pan and fry the burger until golden-brown on both sides. Place the burger onto a baking sheet, top with the Stilton and place under the grill until melted.
Place the chargrilled focaccia bread onto a serving plate and top with the burger.
For the sautéed mushrooms, heat the olive oil in a frying pan, add the mushrooms and fry for 1-2 minutes. Add the garlic, salt and freshly ground black pepper and fry for one minute.
To serve, pile the mushrooms on top of the burger. Sprinkle with thyme leaves and top with the other slice of chargrilled focaccia.
