Over the weekend, I tried these two combinations:
mashed potatoes + cooked eggplant (mashed together): an unusual taste! For some reason, it tastes like a mild sweet potato mash to me.
butter + miso: I used half butter and half barley miso. Maybe it was because the miso was particularly delicious, this was a great combination. Salty, so beware if you are on a low-salt diet! I'm always diluting butter with something else, even if just olive oil (which doesn't reduce the fat, it just modifies the fat). The butter miso mix is my new favorite because the miso does not have many calories.