Put a griddle pan on a high heat and let it get screaming hot.
Pick and finely the rosemary leaves. Mix with a good pinch of sea salt and black pepper and scatter over your clean board. Drizzle olive oil over both sides of the steaks and roll them in the rosemary and seasoning.
Put the yoghurt and horseradish into a small bowl with a pinch of salt and pepper. Squeeze in lemon juice to taste, then add a splash of extra virgin olive oil and mix well. Taste and add a little more horseradish, if needed.
Lay the steaks in your hot pan and press them down gently. Cook for about 1 minute, then turn. Cut the garlic clove in half rub over the hot, charred side of the meat.
Flip the steaks again after another minute, repeat the garlic rub, and press down again. For medium-rare meat, cook for around 3 to 4 minutes on each side. For well-done meat, cook for a few minutes more.
Remove the steaks from the griddle to a plate to rest for a few minutes. Drizzle with a little olive oil to keep them from drying out.
Place the steaks on clean plates and spoon a good dollop of the horseradish sauce on top or next to them. Drizzle some of the lovely resting juices on top. Alternatively you can slice the steaks in half at an angle and serve them on a bed of something light and fresh, like a watercress salad, with the horseradish sauce.