Preheat and prep the pan: Heat your oven to 400°F (200°C). Line a baking sheet with parchment paper or lightly oil it to prevent sticking.
Season the tomatoes: Toss the cherry tomatoes with 1 tablespoon of olive oil, a pinch of salt, black pepper, and red pepper flakes if using. Spread them on one side of the baking sheet.
Season the salmon: Pat the salmon fillets dry with paper towels.
Place them skin-side down on the other side of the sheet. Drizzle with the remaining tablespoon of olive oil, and season with salt and black pepper.
Add lemon and pesto: Spoon the pesto over each fillet, spreading it in an even layer. Sprinkle lemon zest over the salmon and tomatoes.
Drizzle the lemon juice over the tomatoes for brightness.
Bake: Place the sheet pan on the middle rack. Bake for 10–12 minutes for thinner fillets, or 12–15 minutes for thicker pieces. The salmon is done when it flakes easily with a fork and reaches an internal temperature of 125–130°F (52–54°C) for medium.
If you prefer it more done, go to 135°F (57°C).
Optional finish: For golden edges, broil on high for 1–2 minutes at the end. Keep a close eye on it so the pesto doesn’t burn.
Garnish and serve: Sprinkle grated Parmesan over the hot salmon if you like, and scatter fresh basil on top. Serve with lemon wedges.
Pair with rice, quinoa, crusty bread, or a simple green salad.