I was curious when I read Katie Workman’s post in The Daily Beast about the rivalry between Peru and Chile over the potato’s origin. I asked my aunt, who has lived in Lima enough decades to put down her own roots, if it was true. When I received an all caps email from my usually soft spoken aunt, I knew not only was it true, it was serious. I could see why countries would fight over it. Comforting and generous, potatoes lend themselves to almost everything. Regardless of its origin, I was curious to know what Peruvians did with them. She directed me to a friend’s website, Yanuq, an extensive source for traditional and contemporary Peruvian recipes and ingredients. I started looking at recipes for causas, mashed yellow potatoes seasoned with aji amarillo, lime juice, and oil and then stuffed with anything from octopus in olive sauce to chicken and beets. Deciding to start picnic simple, I chose the causa de atún, a jelly roll or brazo gitano style loaf filled with tuna, tomatoes, and avocados. Despite a wide market search, I wasn’t able to find the Peruvian aji amarillo but followed a suggestion on eGullet to use habaneros soaked in milk as a substitute. Still, my market search did bear fruit since I found fresh chirimoyas instead with the sticker declaring them the product of Chile. I wonder what Peru thinks of that?