Preheat your oven to 400°F (200°C). Line two large baking sheets with parchment paper for easy cleanup. This prevents sticking and ensures even roasting.

In a large mixing bowl, combine the sweet potato, broccoli, red bell pepper, yellow bell pepper, zucchini, and red onion. Ensure vegetables are cut to similar sizes for even cooking. Set aside the cherry tomatoes for later.

In a small bowl, whisk together the olive oil, balsamic vinegar, minced garlic, Italian seasoning, sea salt, black pepper, and red pepper flakes (if using) until well combined. This forms the flavorful glaze.

Pour the balsamic herb dressing over the prepared vegetables in the large mixing bowl. Toss gently but thoroughly until all the vegetables are evenly coated. Use your hands for best results!

Divide the coated vegetables evenly between the two prepared baking sheets, spreading them in a single layer. Ensure not to overcrowd the pans, as this will steam the vegetables instead of roasting them to a perfect caramelization. Give them space to breathe!

Roast for 15 minutes. This allows the denser vegetables like sweet potato and broccoli to begin tenderizing.

Carefully remove the baking sheets from the oven. Add the cherry tomatoes to the baking sheets, distributing them among the other vegetables. Gently toss or stir the vegetables. Return to the oven and continue roasting for another 15-20 minutes, or until the vegetables are tender-crisp and slightly caramelized. The sweet potatoes should be fork-tender and the tomatoes slightly burst.

Remove from the oven. If desired, sprinkle with crumbled feta cheese and fresh chopped parsley before serving warm. The feta adds a salty tang and the parsley brightens the flavors.