Preheat the oven to 400°F (200°C) and line or lightly grease a large rimmed baking sheet.
Place the carrots on one side of the prepared sheet pan, drizzle with olive oil, and season with salt and black pepper; toss to coat and spread in an even layer.
Roast the carrots in the oven for 15 minutes.
Meanwhile, in a mixing bowl combine the Italian panko crumbs, dried parsley, minced garlic, lemon zest (and a little lemon juice if desired), salt, lemon-pepper seasoning, smoked paprika, and melted butter; mix until evenly moistened.
After 15 minutes, remove the sheet pan from the oven and add the broccoli and cauliflower florets to the sheet pan; toss gently and push vegetables to make space for the salmon fillets.
Coat the reserved area of the sheet pan with nonstick cooking spray and place the salmon fillets skin-side down on the pan.
Top each salmon fillet with the panko-parmesan-lemon mixture, pressing gently to adhere.
Return the sheet pan to the oven and bake until the topping is golden and the salmon flakes easily with a fork, about 12–15 minutes.
Remove from oven and serve the salmon with the roasted vegetables.
