1.Bake bread rolls following packet instructions.
2.Meanwhile, boil, steam or microwave potato until tender, drain. Push potato through sieve into medium bowl, stir in carrot, tomato, onion, egg white, breadcrumbs and cheese. Shape level tablespoons of mixture into 24 patties, place on baking-paper-lined tray. Cover, refrigerate 1 hour.
3.Meanwhile, make barbecue sauce. Bring tomato sauce, vinegar, sugar, worcestershire sauce and sugar to the boil in small saucepan. Reduce heat and simmer, uncovered, stirring occasionally for about 10 minutes or until thickened.
4.Cook patties in heated oiled large frying pan until browned both sides.
5.Split rolls in half horizontally, cut each roll in half crossways. You will have 24 mini burger buns. Divide patties, lettuce and barbecue sauce between buns.
Patties can be made a day before the party, keep them covered in the fridge. The sauce can be made a week before the party, keep covered in the fridge. Assemble the burgers up to 3 hours before the party.Note