Preheat the oven to 425°F. Line a baking sheet with parchment paper.

In a large bowl, combine cherry tomatoes, bell peppers, zucchini, and red onion. Drizzle with olive oil, then sprinkle with garlic powder, oregano, salt, and pepper. Toss until the vegetables are evenly coated.

Spread the vegetables in a single layer on the prepared baking sheet. Roast in the preheated oven for 20-25 minutes, or until tender and slightly caramelized. Stir halfway through for even cooking.

While the vegetables are roasting, prepare the salad. In a large serving bowl, add the mixed salad greens.

Once the vegetables are done, let them cool for a few minutes before adding them to the salad greens.

Drizzle the balsamic vinaigrette over the salad and toss gently to combine. If using, sprinkle the feta cheese on top before serving.

Serve immediately or chill in the refrigerator for up to 30 minutes before serving for a refreshing taste.