Begin by preheating your oven to 400°F (200°C). Prepare a large baking sheet by lining it with parchment paper or aluminum foil if desired, which will simplify cleanup later. In a mixing bowl, combine the broccoli florets, carrot slices, cubed potato (or sweet potato), and red onion wedges. Drizzle with olive oil and sprinkle with salt, pepper, and optional seasonings such as Italian herbs or red pepper flakes. Toss everything together until the vegetables are evenly coated, then spread them out in a single, even layer on one half of the baking sheet.

Slide the tray into the oven and roast the vegetables for 15 minutes. This initial roasting gives them a head start so they emerge perfectly caramelized and tender.

While the vegetables cook, turn your attention to the fish. Pat the basa fillets dry with paper towels to help them sear and cook evenly. Drizzle olive oil over both sides, then season with salt, pepper, and optional garlic powder or dried herbs for added depth.

After the vegetables have roasted for 15 minutes, carefully remove the baking sheet from the oven. Arrange the seasoned fish fillets on the empty side of the tray. Lay a few thin slices of lemon on top of each fillet for a touch of citrus brightness as it bakes.

Return the tray to the oven and bake for an additional 10 to 15 minutes. You’ll know the fish is done when it turns opaque and flakes easily with a fork. At the same time, the vegetables should be tender-crisp with lightly browned edges. Keep an eye on the fish, as cooking times can vary slightly depending on the thickness of the fillets.

Once everything is perfectly cooked, remove the baking sheet from the oven. Serve the basa fillets immediately, alongside the roasted vegetables, for a balanced and satisfying meal.