Take the Porterhouse steak out of the refrigerator and let it come to room temperature for about 30-45 minutes.

Preheat your grill or grill pan over medium-high heat. Toss the red onion slices with olive oil, salt, and pepper. Grill the onion slices for about 3-4 minutes per side until charred and tender.

In a small bowl, combine lime zest, lime juice, chili powder, garlic powder, smoked paprika, salt, and pepper. Rub this mixture all over the Porterhouse steak.

Place the seasoned steak on the grill over high heat. Sear for about 4-5 minutes on each side for medium-rare.

While the steak is grilling, mix the softened butter with chopped cilantro, additional lime zest, and honey (if using) in a bowl until well combined.

After grilling, transfer the steak to a cutting board and let it rest for at least 10 minutes.

Slice the steak against the grain and serve with the charred red onions and a dollop of chili-lime butter on top.