Heat oven to 200c. Cut the sweet potato into 4cm cubes and the normal potato and peppers into slightly smaller chunks â about 2 1/2cm. Chop the red onion into 8 segments and separate the garlic cloves. Put everything in to the ovenproof dish and coat with the oil. Season with black pepper (no salt needed because halloumi is salty enough). Cook for 45 minutes until the vegetables are soft, sweet and lightly-charred. Then place the cheese and chorizo over the vegetables and whack the oven up to 220c and cook for 10 more minutes until the halloumi is charred too.