The blueberries in this purée give it a fun color and also hide the fact that there's actually a vegetable in it as well, making it a great sneaky and delicious way to get your kid to eat some spinach.
Raw baby spinach should be rinsed well, even if the package says "prewashed." If you’re using frozen blueberries, give them a quick rinse under cold water to thaw a little, and then drain.
Place the spinach in the food processor first and pulse a few times. This will reduce the spinach significantly. Next add the blueberries and 1 tablespoon of water; purée on high until as smooth as possible. Stop occasionally to push the contents to the bottom. If necessary, use another tablespoon of water to create a smooth purée.
This recipe makes about 1 cup of purée; double it if you want to store another cup. It will keep in the refrigerator up to 3 days, or you can freeze 1⁄4-cup portions in sealed plastic bags or small plastic containers.