Step 1: Preheat your oven to 400°F (200°C). Line a large baking sheet with parchment paper for easy cleanup.
Step 2: In a large bowl, combine the broccoli florets, red bell pepper, yellow bell pepper, and red onion wedges. Drizzle with 2 tablespoons of olive oil and sprinkle with garlic powder, onion powder, dried dill, paprika, salt, and black pepper. Toss well to ensure all vegetables are evenly coated.
Step 3: Spread the seasoned vegetables in a single layer on the prepared baking sheet. Place the baking sheet in the preheated oven and roast for 10-12 minutes to give the vegetables a head start.
Step 4: While the vegetables are roasting, pat the salmon fillets dry with paper towels. Drizzle each fillet with a little olive oil, then season generously with salt and pepper.
Step 5: After the vegetables have roasted for 10-12 minutes, remove the baking sheet from the oven. Arrange the salmon fillets among the roasted vegetables on the sheet pan. Place thin lemon slices on top of each salmon fillet.
Step 6: Return the baking sheet to the oven and continue to roast for another 8-12 minutes, or until the salmon is cooked through and flakes easily with a fork, and the vegetables are tender-crisp. Cooking time for salmon can vary based on thickness.
Step 7: Carefully remove the sheet pan from the oven. Serve the sheet pan salmon and roasted vegetables immediately, perhaps with a squeeze of fresh lemon juice for extra brightness. Enjoy your delicious and healthy sheet pan salmon!