Sandwich

A sandwich was an item of food consisting of two pieces of bread with a filling of some sort, originating on, although not limited to, Earth. Sandwiches of grilled meat patties encased in a bun were known as burgers. Condiments like mustard were often used on sandwiches and other "hand-held" foods.

Department Regulation 29d forbade the use of unapproved sandwiches at a picnic. (TV: Fear Itself)

The Doctor
The Third Doctor ate one of the Master's sandwiches during a sword fight with him. He also ate a plateful of cheese sandwiches that Captain Hart had brought for Jo Grant, leaving her only a lettuce garnish. (TV: The Sea Devils)

The Eighth Doctor, Charley Pollard, Viola Learman and Major Ferdinand made and ate sandwiches whilst being held by the Daleks in Mariah Learman's palace in New Britain. (AUDIO: The Time of the Daleks)