Speaking of simple yet addictive, try this one, suggested by our CSA box insert long ago and resurrected after my mom gave us a watermelon radish.
A watermelon radish, in case you don't know, is what Gandalf would be if Tolkien wrote salads instead of books (and you've already met Sauron). Putting radishes and butter on bread is apparently a French thing, and at first glance not related to Tolkein in any way, until you have it as a 10am second breakfast one morning and realize you're going to need to introduce third breakfast as an excuse to eat another before lunch.
Ingredients
Freshly baked bread, sliced
Pasture butter (or a good quality, salted, European-style butter)
Radishes, thinly sliced
Lightly butter the slices of bread, and cover with a single layer of radish.
Seriously, that's it. The crunchy bite of the radish brings out the creamy sweetness of the butter and makes this a perfect mid-morning snack. Or mid-afternoon snack. Or post-dinner pre-dessert snack. Whichever.