Put the carrots in a steamer set over boiling water and cook for 15 to 20 minutes or until tender. Alternatively, put the carrots in a saucepan and add just enough boiling water to cover. Cover and simmer for 15 to 20 minutes or until soft.
Drain the carrots and place in a blender, adding some water from the bottom of the steamer or some of the cooking liquid, then puree until very smooth. The amount of liquid you add really depends on your baby; you may need to add a little more if he finds the puree difficult to swallow. Spoon some of the puree into a bowl and serve lukewarm.