I discovered this simple banana shake while I was pregnant with Zosia. It tastes awesome, and has lots of protein, which us preggers can't get enough of. These days, I've even found that as long as I provide a straw, Zosia loves to drink it too, which is great for a baby who doesn't like to drink much milk.
1 cup milk
1/3 cup nonfat dry milk powder
Squirt of vanilla
Pinch of cinnamon
One Frozen Banana (warning: peel before you freeze it. I found this out the hard way)
Combine in blender and enjoy! It makes a surprisingly filling afternoon snack or even lunch if I drink the whole thing myself. Otherwise, it really makes more of two servings. I imagine it would be an easy recipe to doctor with various other healthful things (flax meal, that sort of thing).