Once ingredients are prepared, preheat the oven to 450ºF. In a large casserole dish, toss together the halved tomatoes, scallions, 2 tbsp oil, 1 tbsp vinegar, minced garlic, ½ tsp salt, ½ tsp pepper and the herb sprigs. Roast tomatoes in the oven until tender, about 15 minutes.
While that roasts, heat the stock until it boils. Stir in the chipped dill, lemon zest and cumin.
Remove the tomatoes from the oven and add the stock, couscous and chickpeas. Cover pan tightly (with foil if necessary) and return to oven for 20 minutes.
After 20 minutes, remove from the oven and remove the lid. Remove the herb sprigs and fold in most of the feta and half of the Parmesan. Then put the remaining feta and parmesan on the top. Bake uncovered until the feta starts to melt, another 5 minutes.