Prepare the Steaks: Take the flat iron steaks out of the refrigerator and let them come to room temperature for about 30 minutes.

Marinate the Steaks: In a small bowl, combine 2 tablespoons of olive oil, calamansi juice, garlic, thyme, smoked paprika, salt, and pepper. Rub this mixture all over the steaks and let them marinate while you prepare the onions and honey butter.

Char the Onions: Heat a grill or grill pan over medium-high heat. Brush the red onion slices with the remaining 2 tablespoons of olive oil and sprinkle with salt and pepper. Grill the onions for about 3-4 minutes on each side until they are charred and tender. Remove from the grill and set aside.

Make the Savory-Infused Honey Butter: In a small bowl, mix together the softened butter, honey, and a pinch of salt. Adjust the sweetness with more honey if desired. Set aside.

Cook the Steaks: Preheat the grill (or a skillet) to high heat. Once hot, add the marinated flat iron steaks. Cook for about 4-5 minutes on each side for medium-rare, or until they reach your desired doneness.

Rest the Steaks: Remove the steaks from the grill and let them rest for about 5-10 minutes. This allows the juices to redistribute.

Serve: Slice the steaks against the grain and arrange them on a platter. Top with the charred red onions and dollops of the savory-infused honey butter. Garnish with fresh parsley before serving.