Preheat oven to 400°F.
In a large baking dish, combine the cherry tomatoes, fennel (or shallot/onion), garlic, and capers. Drizzle with olive oil, vinegar, and honey; season with salt, pepper, and chili flakes. Toss to coat.
Nestle the cod fillets into the vegetable mixture and top with lemon slices.
Bake for 15-18 minutes, until cod is opaque and flakes easily with a fork.
Garnish with fresh basil leaves before serving.
