Preheat oven to 425 degrees. Place the zucchini, yellow squash, bell pepper, and tomatoes on a rimmed baking sheet. Drizzle with half the olive oil and season with salt and black pepper to taste.
Roast for 20-25 minutes or until softened and lightly browned. Set aside.
Meanwhile, heat the remaining olive oil over medium-high heat in a large skillet or saute pan.
Add the onion, reduce heat to medium-low, and cook for 5-7 minutes or until it softens.
Add the garlic and cook briefly or until aromatic, 5-10 seconds.
Add the barley and stir until it's coated with oil and lightly toasted, approximately 1 minute.
Add the wine, bring to a boil and cook until the wine is almost evaporated, 1-2 minutes. Lower heat to medium.
Add approximately 2 cups of vegetable (or chicken) broth, crushed tomatoes, and Italian seasoning. Simmer uncovered, stirring occasionally until the broth is absorbed, 5-7 minutes.
Repeat with another cup of the vegetable (or chicken) broth. Simmer, stirring occasionally until the broth is absorbed, 5-7 minutes. Test the barley to determine doneness. If it's tender but still has some "bite" to it, it's done. If not, add more of the remaining broth and continue cooking for another 5-7 minutes or until the barley is tender but still al dente.
Stir in the roasted vegetables, grated Parmesan cheese, and basil.
Season with salt and pepper to taste.
Serve in bowls garnished with additional Parmesan and more fresh basil.