I think so much about the food people ate pre-Columbian exchange. Huge parts of cuisine extremely important on both sides of the pond just didn't exist.
You've probably heard a little about what was brought over from the New World, corn, potatoes, cocoa, cassava, peanuts, chili peppers, avocadoes, cranberries, pumpkins, and the like. Imagine cooking without chili! Without potatoes! Modern Indian cuisine contains enormous amounts of potatoes and we just didn't have those for the vast majority of history. The best of the nightshades all on one contiguous hunk of land. Hell, tomatoes! Almost forgot about those.
But we don't often look at what the Old World had. Wheat! Barley! Rice! A profusion of incredible grains, really, the finest poaceae has to offer. Carrots! Tons of rosaceous plants like apples and cherries and pears and peaches and apricots! Grapes! Soy and Bamboo! Okra and watermelon! All these things were simply never found in the Americas. The grains one is the wildest for me, the variety of grains available across Eurasia and Africa was truly astounding.
You know what binds together the food of all cultures across the world? Onions. Onions are fucking everywhere. There's probably onions growing near you right now. Allium Gang Unite.