A machine that mixes it for you doesn't count? Or this: http://www.breyers.com/product/detail/113883/vanilla-chocolate-ice-cream http://www.breyers.com/product/

A machine that mixes it for you doesn't count? Or this: http://www.breyers.com/product/detail/113883/vanilla-chocolate-ice-cream http://www.breyers.com/product/detail/113883/vanilla-chocola... And either way, the challenge would allow chocolate topping to a vanilla icecream base, or chunks of chocolate in a vanilla ice cream. Both of which are extraordinarily common.