This has become a big favorite of mine lately. I would say I have this snack at least 5 times a week, although I often replace the toast with a few unsalted peanuts. The taste of the apple mixed with that of the almond butter and cinnamon is really interesting.
I find Red Delicious or Gala work best for this combination, but I think any apple could work, really. Likewise, I tend to use almond butter, but any nut butter would do the trick. Whatever direction you decide to take, this is a great way to keep your tummy happy when lunch is far gone and dinner seems so far away!