Most restaurateurs are acutely sensitive to changing the menu. They understand the dynamic exercises that are required to change even a letter on their menu. There is a way to completely improve the dining experience without having your accountant go ballistic. Increase the number of condiments you have available.
There are three benefits to this strategy.
1) The basic menu is unchanged.
2) Operating cost increase is negligible.
3) The variety that your existing menu offers has just gone parabolic and the guest experience has improved.