1) Preheat the oven to 200C/Gas 6.
2) Peel 5 cloves garlic and place them in a square of foil. Sprinkle the cloves with salt and pepper and drizzle with 2 tbsp olive oil. Wrap up the foil and place it directly on the oven rack. (Be sure that the foil packet is secure so no oil will leak out.) Roast the garlic until it's brown and tender, about 25 mins. Allow to cool enough to touch and squeeze the garlic from the skins. Set aside.
3) Saute onions and carrots with the oil in a medium saucepan. Add tomato puree and stir well. This will cook off the tomato puree and give a nice orangey color. Cook for about 10 mins. When vegetables are softened add the roasted garlic, salt, pepper, basil, oregano and stir together until incorporated. Pour in the tomatoes. Fill the empty tin with water and add it to the pan. Bring to a boil then lower the heat to a simmer. Simmer for 1 hr, uncovered. Stir occasionally. Once sauce is ready carefully pour it into the food processor and puree until smooth.