01 - Preheat oven to 425°F. Line a large baking sheet with parchment paper or foil.
02 - In a small bowl, whisk together olive oil, lemon juice, garlic, Dijon mustard, honey, salt, black pepper, and smoked paprika until well combined.
03 - Place green beans and sliced red onion on the baking sheet. Drizzle with half the marinade and toss to coat evenly, spreading them in a single layer.
04 - Arrange salmon fillets on top of the green beans. Brush the salmon generously with the remaining marinade, ensuring even coverage.
05 - Roast for 15-18 minutes, or until salmon is cooked through and flakes easily with a fork, and green beans are tender-crisp.
06 - Remove from oven and immediately drizzle melted butter over salmon and vegetables. Garnish with chopped parsley and serve with lemon wedges on the side.