Preheat your oven to 200°C/Fan 180°C/Gas 6. Trim the base off the cauliflower and slice into bite-size florets. Scatter onto a roasting tin and sprinkle over 1 tbsp cumin seeds and a little salt and pepper. Pour over 1 tbsp oil and toss together till evenly coated. Tuck in the 2 unpeeled garlic cloves.
Halve the cherry tomatoes and arrange in a second roasting tin. Sprinkle over a pinch of salt and pepper. Slide both the cauliflower and tomato roasting tins into the oven and roast for 20 mins, till the cauliflower is golden and slightly charred.
Meanwhile, pour the bulgar wheat into a large bowl. Top up with 300ml boiling water and cover the bowl with a plate. Set aside for 15 mins.
Peel the red onions and finely slice them. Pour 1 tbsp olive oil into a pan and warm to a medium heat. Slide in the onions and sprinkle in a pinch of salt and pepper. Pop a lid on the pan and cook for 15 mins, stirring occasionally, till soft and slightly caramelised.
Roughly chop the rocket. Fluff the cooked bulgar wheat with a fork. When the tomatoes have roasted, stir them through the bulgar wheat along with the caramelised onions and chopped rocket. Grate in the lemon zest and squeeze in the juice. Squeeze the soft garlic flesh out their skins and finely chop. Stir through the bulgar wheat along with a little salt and pepper and 1 tbsp oil.
Pile the bulgar wheat onto plates and top with chunks of roasted cauliflower. Sprinkle over a good pinch of sumach and serve with generous dollops of yogurt.