When Nat was younger she was a pickier eater and still goes easier on the animal protein - like she self-selects toward being vegetarian (nobody in our house is, not even close! LOL). At the time, though, it was veggies she avoided so I was looking for something with veg in it too, to supplement.
I have been known to use this protein powder with rice milk in smoothies for her when she was smaller:
http://www.rainbowlight.com/protein-weight-management-protein-energizer-chocolate.aspx; there is also a vanilla version. (I know it says "weight management" on the link but we used it in conjunction with good fats since the actual nutrition was our concern.) I'd put a spoonful in a sports bottle of rice milk, shake it up, and that's what she'd have for breakfast - for about a year or more!
Even now I'll put some in smoothies with yogurt & coconut milk for ME (although I'll share with the girls). The protein powder is dairy-free, nut-free, soy-free, the works, and there are also some dried greens in there to boot.