Preheat oven to 425°F (220°C). Line two large rimmed baking sheets with parchment paper or lightly oil them. Wash and dry all vegetables. Cut baby potatoes in half (quarter if very large), slice carrots into 1/2-inch sticks, separate broccoli into bite-size florets, core and slice the red bell pepper, cut the red onion into wedges, and slice the zucchini into rounds or half-moons. Try to keep pieces relatively uniform so they roast evenly.

If using denser vegetables (potato, carrot), place them on one baking sheet; place quicker-roasting veggies (zucchini, broccoli, bell pepper, onion) on the second sheet so you can remove the faster-cooking ones earlier if needed.

Seasoning

Make the seasoning mixture

In a small bowl, whisk together the extra-virgin olive oil, fresh lemon juice, minced garlic, dried oregano, smoked paprika, red pepper flakes, salt, and black pepper until combined.

Divide the seasoning mixture roughly: reserve about 1 tablespoon for finishing drizzle and use the rest to coat the vegetables.

Roasting

Toss vegetables with seasoning

Place the potatoes and carrots in a large bowl or directly on their prepared baking sheet. Pour about two-thirds of the seasoning mixture over them and toss well to coat. Spread them out in a single layer with space between pieces (crowding causes steaming). Repeat with the second sheet of broccoli, bell pepper, red onion, and zucchini, using the remaining seasoning (except the reserved tablespoon).

Roast

Slide the baking sheet with potatoes and carrots into the oven on the middle rack. Roast for 15 minutes. After 15 minutes, put the second sheet with the quicker-cooking vegetables on a lower or upper rack (not directly above the potatoes to avoid steaming). Roast both sheets for another 12–18 minutes, checking after 10–12 minutes. Vegetables are done when potatoes are tender and golden-brown and other vegetables are nicely caramelized at the edges and fork-tender. Total roasting time for potatoes may be about 25–30 minutes; quicker vegetables may take 12–20 minutes depending on size.

If certain vegetables finish earlier, remove their sheet and continue roasting the remaining ones until all are done.

Finish & Serve

Final seasoning and assembly

When vegetables are roasted, transfer them to a serving platter or mix them gently in a large bowl. Drizzle the reserved tablespoon of seasoning mixture over the hot vegetables and add the fresh parsley, toasted pine nuts or chopped almonds (if using), and lemon zest. Taste and adjust salt, pepper, or lemon as needed.

Serve warm as a main for a plant-based meal alongside grain (quinoa, rice) or as a side to proteins. Leftovers keep well in the refrigerator for 3–4 days and reheat in a 400°F (200°C) oven for 8–10 minutes to re-crisp.