Let me start by saying that, although I am not a food snob, I do have principles when it comes to food. I sous'd in a French joint for a few years, used to supplement my income baking upscale wedding cakes. But I love a good hot dawg, make a meatloaf that is the envy of all my friends and will resort to bottled Spag Sauce when necessary.
SO, when my boyfriend (now my husband) suggested I try his favorite fuel-up-for-a-bike-ride sandwich, I gagged at the thought: tuna salad on bread spread thickly with peanut butter. I watched in horror a few times as he whipped up his bag lunch in the morning (after making the most delicious omelettes or French toast or, my fave, Toad-in-a-hole; it just didn't add up). In time, though, curiosity got the better of me, and my faith in his culinary aptitude solidified (he makes exquisite paella). I finally tried it -- just a bite at first, and then a few.
And then it happened. I was home alone, it was lunch time, I was going to ride later in the day. And there were all the ingredients, beckoning. I felt terribly guilty putting it all together, but let me say that it was delicious. A classic "greater than the sum of its parts" situation. And nutritionally, it had all the right stuff for sports.
We've experimented some with the formula. In general, lots of onion in the tuna mix with more rather than less mayo. Smooth peanut butter. The bread is important: don't try this with Wonder Bread, kids. Chewy, crusty something works best. And then there's the "Asian" variant: add lime juice and copious quantities of chopped fresh cilantro to the tuna mix, and use crunchy PB. We even went so far as to try PB with caviar, on Westphalian pumpernickel points with chopped onion (low suck factor, indeed).
The Mungo Sandwich -- you heard it here first. I won't tell where the name comes from. SOME things are best left to the imagination.