Using a food processor or blender, blend organic brown rice until it is finely ground, like a flour. Boil some water in a saucepan with a lid, about 2 cups, slowly whisk in about 1/4 cup of the rice flour. Cover and turn down to minimum heat. Stir every 2 minutes for 10 minutes.
This will last in the refrigerator for 2 or 3 days. As your baby gets older, you can begin using all sorts of different grains and then legumes such as brown rice, oatmeal, millet, garbanzo beans and black beans. Just blend into flour and cook.