Let the T-bone steak sit at room temperature for about 30 minutes before cooking. Preheat your grill or skillet over medium-high heat.

Pat the steak dry with paper towels. Season both sides generously with salt and the cracked black peppercorns, pressing the pepper into the meat to adhere.

Add 2 tablespoons of butter to the skillet or grill. Once melted and bubbling, place the steak in the pan. Cook for about 4-5 minutes on one side, then flip and cook for another 4-5 minutes for medium-rare, or until desired doneness. Use a meat thermometer to check for an internal temperature of 130°F (54°C) for medium-rare.

In the last 2 minutes of cooking, add the minced garlic and remaining butter to the pan. Baste the steak with the melted garlic butter using a spoon.

Once cooked to your liking, remove the steak from the heat and let it rest on a cutting board for at least 5-10 minutes to allow the juices to redistribute.

In a small saucepan, heat the olive oil over medium heat. Add the chopped onion and sauté until translucent.

Stir in the red currant jelly and balsamic vinegar. Cook for about 5-7 minutes, stirring frequently, until the sauce thickens slightly.

Slice the T-bone steak against the grain. Drizzle the red currant and onion reduction over the steak slices. Garnish with fresh thyme leaves and serve immediately.