Steak sandwich with horseradish

Preheat oven to 240 ºC. Place the garlic in a small baking dish and sprinkle with a little oil and salt. Cover and bake in the oven for 20 minutes or until the garlic is soft.
While the garlic is cooking, heat 15 ml oil in a heavy-based frying pan over low heat. Cook the onion for 8-10 minutes or until golden. Set aside and keep warm.
Put tomato slices in pan and cook for 2 minutes on each side, or until browned. Set aside and keep warm.
Add a little more oil to the pan and cook the mushrooms over medium heat for 4-5 minutes, or until soft. Remove from the pan and keep warm.
Combine the butter and horseradish sauce and season with salt and pepper. Lightly toast the slices of bread and spread with the horseradish butter.
Cut the fillet into 1 cm-thick slices. Brush each slice of meat with a little olive oil and cook in batches for 1 minute on each side. Top toast with tomato, steaks, mushrooms and onion.
Sprinkle with cracked black pepper and serve immediately with roasted garlic and rocket salad. Serves 4.