Fill a pot with about 1 inch of water, add peas to a steamer basket and place inside of the pot. Bring water to a low boil, cover with lid and steam peas for 3-6 minutes, or until bright green and tender. Remove from heat and let peas cool.
Place peas in a blender or food processor and blend, adding liquid (breast milk, formula or water) as needed to get the desired consistency.
Store pea puree in the fridge for 3-4 days or in the freezer or up to 3 months. I like to freeze the puree in silicone ice cube trays or small freezer-safe jars so I can easily thaw small amounts when I want to use them.
I recommend thawing frozen puree in the fridge the night before you want to use it, but you can also thaw it quickly with a warm water bath.
Notes
If you want to add the most nutrition to the puree, I recommend using breastmilk or formula instead of water to thin the pea puree.