Pre heat the oven to 180 C. Slice the tomatoes in ½ and lay on a baking sheet, season with sliced garlic, thyme, a sprinkle of salt, sugar and pepper, olive oil and balsamic vinegar. Roast for 1 hour or until their size has reduced by half. Keep warm.
Heat a griddle pan over a high heat. Cube the halloumi into bite sized pieces and griddle until a good dark crust is formed. Break the lettuce up and wash thoroughly. Drain and keep to one side.
Put the vinaigrette ingredients into a blender. Pulse until smooth and emulsified. Add water to get a pouring yet coating consistency. In a bowl combine the lettuce, tomatoes, halloumi with 8 tablespoons of the dressing, toss together and serve immediately.