Step 1: Preheat your oven to 400°F (200°C). Line a large baking sheet (or two, if needed, to avoid overcrowding) with parchment paper for easy cleanup.
Step 2: In a large mixing bowl, combine the broccoli florets, bell pepper pieces, red onion wedges, zucchini slices, and cherry tomatoes.
Step 3: In a small bowl, whisk together the olive oil, lemon juice, minced garlic, chopped fresh rosemary, chopped fresh thyme, dried oregano, salt, pepper, and optional red pepper flakes.
Step 4: Pour the lemon-herb dressing over the vegetables in the large mixing bowl. Toss thoroughly until all the vegetables are evenly coated. Ensure every piece is glistening with the fragrant marinade.
Step 5: Spread the seasoned vegetables in a single layer on the prepared baking sheet. Do not overcrowd the pan; if necessary, use a second sheet pan to ensure proper roasting and browning. Overcrowding will steam the vegetables instead of roasting them.
Step 6: Roast for 25-30 minutes, or until the vegetables are tender-crisp and lightly caramelized. Halfway through cooking (around 15 minutes), gently toss the vegetables to ensure even roasting. Keep an eye on them, as oven temperatures can vary.
Step 7: Once roasted to perfection, remove from the oven. Serve immediately as a stand-alone meal, or alongside your favorite protein. A final squeeze of fresh lemon juice before serving can brighten the flavors even further.