Steam the broccoli till bright green and softened, in a small pot with about 1/4 cup water.
IF you have an immersion blender, you can then simply toss the other ingredients in the pot, blend in there, and ta-da, your smoothie's made! Or you can transfer the broccoli and the rest to a blender or food processor.
Be sure to blend very well, especially if trying to hide veggies from children- and in that case, probably a good idea to use a sweeter yogurt or add the honey. However, it's entirely optional.
Note: For the soy yogurt, I use homemade tofu sour cream- just soft tofu blended with lemon juice to taste and a pinch of salt.