Remove the tomahawk steak from the refrigerator and let it sit at room temperature for about 30-45 minutes before cooking.

Preheat your grill or smoker to a medium-high heat.

In a small bowl, combine the smoked sea salt, cracked coriander, and black pepper.

Rub the olive oil all over the steak, then generously coat the steak with the spice mixture, ensuring an even coverage on all sides.

Place the tomahawk steak on the preheated grill or smoker. Cook for about 4-5 minutes on each side for medium-rare, or until it reaches your desired doneness. Use a meat thermometer to check the internal temperature (130°F for medium-rare).

Once cooked, remove the steak from the grill and let it rest for at least 10-15 minutes to allow the juices to redistribute.

In a skillet over medium heat, melt 2 tablespoons of the softened butter. Add the finely chopped sweet onion and sprinkle with brown sugar. Cook, stirring occasionally, until the onions are caramelized and golden brown (about 10-15 minutes).

Stir in the balsamic vinegar and season with salt and pepper to taste. Remove from heat and let cool slightly.

In a mixing bowl, combine the remaining softened butter with the caramelized onions, mixing well. Transfer the compound butter to a piece of parchment paper, roll it into a log, and refrigerate until firm.

Slice the rested tomahawk steak against the grain and serve with slices of the caramelized sweet onion compound butter on top. Garnish with fresh herbs if desired.