Preheat the oven to 400°F (200°C).
In a medium pot, combine lentils and broth or water. Bring to a boil, then reduce heat and simmer for 20-25 minutes, until tender.
While lentils are cooking, spread diced vegetables (bell pepper, zucchini, cherry tomatoes, and red onion) on a baking sheet.
Drizzle with olive oil, and sprinkle oregano, garlic powder, salt, and pepper over the veggies. Toss to coat evenly.
Roast in the oven for 20-25 minutes or until veggies are tender and slightly caramelized.
In a large bowl, combine cooked lentils, roasted vegetables, mixed greens, balsamic vinegar, and lemon juice. Toss gently to mix all ingredients.
Serve warm or at room temperature. Enjoy!