- In a pot over high heat, cook the onions in the butter until very caramelized, about 5 minutes. Add the broth and bring to a boil. Simmer until the sauce has reduced by one-third, about 10 minutes. Remove from the heat.
- Using a hand blender, purée the mixture until smooth.
- In a small bowl, whisk the cornstarch into the soy sauce.
- Whisk the cornstarch mixture into the sauce. Bring to a boil. Simmer until the sauce is smooth and thickened. Add the hot sauce. Cover and keep warm.
- Meanwhile, place the halloumi slices in a bowl. Cover with cold water and let sit for 10 minutes to remove some of the salt. Drain and pat very dry. Place on a large plate with the green onions. Coat in 1 tbsp (15 ml) of the oil.
- Place a 10-inch (25 cm) wide, 2-inch (5 cm) deep cast iron pan directly on the barbecue grill. Preheat the grill, setting the burners to medium-high.
- In a bowl, combine the potatoes with the remaining oil and the oregano. Season with salt and pepper.
- Overlap two large pieces of foil. Place the potatoes on the foil and spread out into an even layer. Tightly seal the foil into a packet. Place the packet directly on the grill and cook for 15 minutes or until tender.
- Meanwhile, place the cheese in the hot cast iron pan. Cook for 5 minutes or until nicely golden, turning over halfway through. Cook the green onions directly on the grill for 5 minutes or until starting to soften. Remove the potatoes, cheese and green onions from the barbecue. On a work surface, dice the cheese and thinly slice the green onions.
- Serve the potatoes in bowls topped with the cheese and green onions. Cover with the hot sauce. Serve immediately.
If you don’t have a cast iron pan, you can grill the halloumi directly on a well-oiled grill.