Possible Clues:

• Not part of a restaurant's set meal
• Separately, on menus
• Sounds like how 26 across may get the takeaway from the restaurant
• Course specification
• Menu of individual dishes with separate prices
• Alternative to 17 across
• Menu type
• The pick-what-you-like menu
• Billing option that favors purchasing individual items rather than packages
• Alternative to prix fixe