Remove the skin from the cod fillets using a very sharp flexible knife so that you have the skin (you can ask your fishmonger to do this for you as well). Wrap the cinnamon sticks in the skin and put to one side.
Line the base of a steamer with nonstick baking paper and sit the 4 cod fillets on top of the paper. Drizzle a little of the olive oil on top and season well, then sit the wrapped cinnamon sticks on top of the cod. Bring a saucepan of water to a simmer over a moderate heat and sit the steamer on top. Let the steam cook the fish for 8-10 minutes until just cooked.
Meanwhile, combine the tomato with the remaining olive oil and the basil to create a simple sauce. Remove the cod and cinnamon sticks from the steamer and arrange the cod on serving plates. Top with tablespoons of the sauce followed by the wrapped cinnamon sticks. Serve immediately.