My son is 2 now, and allergic/sensitive to a few things, but one of our staples is a home-made polenta and buckwheat pancake with spinach cut up really small and mixed into the batter. They are so healthy but delicious!
I guess you could use a mix and just put the spinach in the batter if that's easier, although from scratch its really simple too. Let me know if you want the recipe.
You could vary what you put into the batter - one mom I know puts spinach and cheese in, but you could put all sorts of chopped up veggies - use the Cuisinart to cut them up. Once the little pancakes have been cooked, we make mini sandwiches with either hummus or peanut butter and either fold the little pancakes over in half with the filling inside, or put two similar sized ones together with the filling in between. I think you could put lots of different stuff inside, but my son's favorite is hummus by far, and I love that he's getting spinach and isn't fighting it! We've been having these since he was under a year. Let me know if you want the recipe, its really easy.
My son also really likes carrots and cucumber dipped in hummus, which is another nutritious one, but fun because of the dipping.