When it comes to a lone dessert item on the list, it's a tough call between the excellent Argentinian helado and the alfajor.
The alfajor is a staple in the Argentinian dessert diet. The tasty treat is a simple flour vanilla biscuit, stuffed with dulce de leche, and then usually rolled on the sides in coconut. Chocolate covered options are also popular. You'll find brands such as Cachafaz, one of the most popular brands, in ever kiosk market, and chain stores like Havana are popular. But for the best experience, one should try a bakery where you know they are fresh, soft, and perfect.