Place the zucchini, squash, onion, asparagus and mushrooms in a large bowl; add in garlic, olive oil and sugar, and stir gently to coat vegetables. Spread vegetables in a single layer on a baking tray and sprinkle with salt and pepper.
Roast vegetables until tender, 20 to 25 minutes.
Meanwhile, bring a large pot of lightly salted water to boil. Add stock cubes, wine and risoni, and cook until al dente, about 8 to 10 minutes. Drain. Stir in roasted vegetables and Parmesan cheese, and serve warm.