Preheat your oven to 400°F (200°C). Wrap the whole head of garlic in aluminum foil and roast in the oven for about 30-35 minutes, or until the cloves are soft and caramelized. Remove from the oven and let cool slightly. Squeeze the roasted garlic cloves out of their skins and set aside.

In a bowl, combine the softened butter, roasted garlic, chopped porcini mushrooms, cracked Szechuan peppercorns, fresh parsley, and a pinch of salt. Mix well until everything is fully incorporated. Transfer the mixture onto a piece of parchment paper, roll it into a log shape, and refrigerate until firm, about 30 minutes.

While the butter is chilling, rub the T-Bone steaks with olive oil, chopped tarragon, salt, and pepper. Make sure to coat them evenly. Let them sit at room temperature for about 30 minutes to enhance the flavor.

Preheat a grill or cast-iron skillet over medium-high heat. Once hot, add the steaks and cook for about 4-5 minutes on each side for medium-rare, or until your desired doneness is achieved. Use a meat thermometer for accuracy (130°F for medium-rare).

Once cooked, remove the steaks from the heat and let them rest for 5-10 minutes. This allows the juices to redistribute throughout the meat.

Slice the chilled compound butter and place a piece on top of each T-Bone steak just before serving. Garnish with additional fresh tarragon if desired.