Saute onion and carrots (if using) in olive oil in a large pot until softened, about 5 minutes.

Add chopped broccoli florets and enough water to almost cover, about 2-2.5 cups. You don't want to over do it, or the soup will be too runny. The amount of water really depends on how large the head of broccoli is.

Cover pan and bring to a boil, then reduce to a simmer. Simmer until broccoli is tender, but still bright green. Keep an eye on it, you don't want it to lose all the nutrients!

Once cool, you can freeze it in an ice cube tray and then put the cubes in freezer bags for warming up later. I like to do this so I always have something healthy on hand for Baby Bee.