1. Heat oil in a large nonstick skillet over medium-high heat. Add carrot and onion, and cook 4 to 5 minutes until onion begins to brown. Add garlic and thyme; cook 1 minute until fragrant.
2. Reduce heat to medium; stir in barley and white wine (if using) or ï¿½ cup broth. Cook 1 minute until liquid is absorbed. Add zucchini, bell peppers, and ï¿½ cup broth; cook 4 to 5 minutes, stirring occasionally, until liquid is absorbed. Add remaining ï¿½ cup broth; cook until vegetables are tender and most of the liquid has been absorbed. Season with ï¿½ teaspoon salt and freshly ground black pepper.
3. Stir in peas; remove from heat. Let risotto rest 1 to 2 minutes until peas are thawed but still bright green. Stir in Parmesan cheese just before serving.