Preheat your oven to 400°F (200°C). Take the whole garlic cloves, place them on a small piece of aluminum foil, drizzle with olive oil, and wrap them up tightly. Roast in the preheated oven for about 25-30 minutes, or until tender and fragrant. Remove from the oven and let cool slightly.

In a bowl, combine the softened butter with the roasted garlic (squeeze to extract the garlic from the skins), fresh thyme leaves, and a pinch of salt and pepper. Mix until well combined. Set aside.

Heat a grill pan or regular skillet over medium-high heat. Drizzle the onion rings with olive oil and season with salt and pepper. Once the pan is hot, add the onions and cook for about 3-4 minutes on each side until charred and softened. Remove from the pan and set aside.

Season the ribeye steaks generously with salt and pepper on both sides. In the same pan used for the onions, add a little more olive oil if necessary, and increase the heat to high. Once hot, add the steaks and sear for about 4-5 minutes on each side for medium-rare, or until desired doneness is reached. During the last minute of cooking, sprinkle the pomelo segments on top of the steaks, allowing them to warm slightly.

Once cooked to your liking, remove the steaks from the pan and let them rest for about 5 minutes to allow the juices to redistribute.

Place the rested steaks on a serving platter. Top with the charred red onion rings and drizzle with any reserved pomelo juice. Add dollops of the roasted garlic and thyme butter on top of each steak. Garnish with fresh thyme sprigs if desired. Serve immediately.