1/4 cup plain yogurt
1 egg yolk
1 tablespoon olive (or other) oil
about 3/4 cup potato starch
1/8 teaspoon baking soda
Herbs or cheese
Mix the liquid ingredients first. Add the baking soda to 1/2 cup of potato starch and mix it into the wet ingredients. Then add more starch, a tablespoon or so at a time, until it becomes difficult to stir. Be careful -- if you add too much, it will become impossible to stir! Add in some salt, herbs, or whatever your baby likes. Next time I think I'll try some rosemary.
Spread the batter out thinly on a Silpat or sheet of parchment paper placed on a cookie sheet. Sprinkle with grated cheese, if desired. Bake at 350 degrees for 15-20 minutes, or until dry. Cut into crackers with a knife or pizza cutter -- you may need to break them up with your hands after scoring them with the knife. Store in an airtight container, if you want an actual edible cracker. If you leave them on the counter, you'll get a teething biscuit that will stand up to hours of chewing, without much cracker ending up inside the baby. ;) They get stale really easily. I've been keeping one in my pocket when we go out, so the baby can have something to chew on and taste without making a mess.
Egg yolk is rich in iron and not allergenic like egg whites are. For even more iron, add a bit of blackstrap molasses to the wet ingredients.