Preheat your grill to medium-high heat.
In a mixing bowl, combine the cherry tomatoes with 1 tablespoon of olive oil, salt, black pepper, and garlic powder.
Spread the tomatoes on a baking sheet and roast in the oven at 400°F for about 15-20 minutes, or until they are blistered and soft.
While the tomatoes are roasting, brush the cod fillets with the remaining tablespoon of olive oil and season with salt and pepper.
Place the fillets on the grill and cook for about 4-5 minutes per side, or until the fish flakes easily with a fork.
In a small bowl, mix together the sour cream, dill, lemon juice, and Dijon mustard to create the creamy dill sauce.
Once the cod is cooked and the tomatoes are roasted, serve the cod topped with the roasted tomatoes and drizzle the creamy dill sauce over the top.