Preheat your grill or grill pan to medium-high heat.

Trim the root ends of the spring onions and place them on a baking sheet. Drizzle with olive oil and sprinkle with salt and black pepper. Toss to coat evenly.

Grill the spring onions for about 5-7 minutes, turning occasionally, until they are charred and tender. Remove from the grill and set aside.

While the spring onions are grilling, prepare the sirloin steaks. Pat them dry with paper towels and season generously with salt and black pepper.

In a small bowl, combine the key lime zest and juice. Brush the mixture over both sides of the sirloin steaks.

Once the spring onions are done, place the sirloin steaks on the grill. Cook for 4-5 minutes on each side for medium-rare, or until your desired doneness is reached. Use a meat thermometer to check for an internal temperature of 130°F for medium-rare.

While the steaks are grilling, make the jalapeño-cilantro butter. In a bowl, mix the softened butter, chopped jalapeño, and cilantro until well combined. Season with a pinch of salt.

Remove the sirloin steaks from the grill and let them rest for 5 minutes.

To serve, place the grilled sirloin steaks on a platter, top with the burnt spring onions, and dollop the jalapeño-cilantro butter on top.

Enjoy your delicious Burnt Spring Onion and Key Lime-Crusted Sirloin with Jalapeño-Cilantro Butter!