My friends and I have recently started a short list of those ingredients that are so delicious that they make both pizza and ice cream taste better. Here it is thus far:
-Peanut butter (Peanut butter chocolate swirl ice cream; Thai chicken pizza)
-Creme fraiche (Add a dollop to any home-made ice cream to make it richer and creamier; creme fraiche, caramelized onion, and roasted mushroom pizza)
-Balsamic Vinegar (raspberry and reduced balsamic ice cream; lightly drizzle balsamic or balsamic reduction over margherita pizza)
That's all we have so far. Any other suggestions? If you do have any, recipes are strongly encouraged.