01 - Preheat oven to 400°F. Line a baking sheet with parchment paper or lightly grease a baking dish.
02 - Arrange salmon fillets on the prepared baking sheet. Season each fillet with salt and pepper.
03 - Spread approximately 1 tablespoon of pesto over the top of each salmon fillet.
04 - In a mixing bowl, toss cherry tomatoes and red onion (if using) with olive oil, a pinch of salt, and pepper.
05 - Scatter the seasoned tomatoes and onion around the salmon fillets on the baking sheet.
06 - Bake for 15 to 18 minutes, or until the salmon flakes easily with a fork and the tomatoes are roasted and tender.
07 - Plate the salmon and vegetables. Garnish with fresh basil leaves and serve with lemon wedges.