In a small bowl, combine the softened butter, balsamic vinegar, honey, and garlic powder. Mix until well combined. Transfer the mixture onto a sheet of parchment paper, roll it into a log, and twist the ends to seal. Refrigerate until firm, about 30 minutes.

Preheat your oven to 400°F (200°C).

Pat the T-Bone steaks dry with paper towels. Season both sides generously with salt and freshly ground black pepper. In a skillet over medium heat, add the whole mustard seeds. Toast them, stirring occasionally, until they start to pop and become fragrant, about 2-3 minutes. Remove from heat and let cool slightly.

In a small bowl, combine the toasted mustard seeds and chopped sage. Rub the olive oil over the steaks, then press the mustard seed and sage mixture onto both sides of the steaks to form a crust.

In an oven-safe skillet, heat a bit of olive oil over medium-high heat. Once hot, add the T-Bone steaks to the skillet. Sear for about 4-5 minutes on each side until they develop a nice brown crust.

Transfer the skillet to the preheated oven and roast the steaks for an additional 5-10 minutes, depending on your desired doneness (5 minutes for rare, 7 minutes for medium-rare, and 10 minutes for medium).

Remove the skillet from the oven and transfer the steaks to a cutting board. Let them rest for 5-10 minutes.

Slice the compound butter into rounds and place on top of the warm steaks to melt. Garnish with fresh sage leaves before serving.