Preheat the oven to 450 F.
Arrange the tomatoes on a nonstick baking sheet. Drizzle with 1 tablespoon of the olive oil and sprinkle with 1/4 teaspoon of the salt and 1/4 teaspoon of the pepper. Toss gently to mix. Roast until the tomatoes are softened and beginning to brown, 25 to 30 minutes. Set aside 16 tomato wedges to use for a garnish.
In a saucepan, combine the vegetable stock and water and bring to a boil over high heat. Reduce the heat to low and keep at a simmer.
In a large, heavy saucepan, heat the remaining 1 tablespoon olive oil over medium heat. Add the chopped shallots and saute until soft and translucent, 2 to 3 minutes. Stir in the white wine, if using, and cook until most of the liquid evaporates, 2 to 3 minutes. Stir in the barley and cook, stirring, for 1 minute. Stir in 1/2 cup of the stock mixture and cook until the liquid is completely absorbed, stirring occasionally. Continue stirring in the stock mixture in 1/2-cup increments, cooking each time until the liquid is absorbed before adding more, until the barley is tender, 45 to 50 minutes total. Remove from the heat and fold in the tomatoes, chopped basil, parsley, thyme and grated cheese. Add the remaining 3/4 teaspoon salt and 1/4 teaspoon pepper and stir to combine.
Divide the risotto among warmed individual shallow bowls. Garnish with the reserved roasted tomato wedges and the whole basil leaves. Using a vegetable peeler, cut a curl or two of Parmesan cheese for topping each serving.