1 Steam sweet potato and carrots in a microwave or on the stovetop for 8–10 minutes, or until tender. Transfer vegies to a large bowl, mash lightly and set aside.
2 Meanwhile, heat 1 teaspoon of olive oil in a small non-stick frying pan set over medium heat. Add onion to pan; cook for 2 minutes, or until almost soft. Add curry paste to pan; cook for another 2 minutes. Add baked beans to pan; simmer, stirring regularly to stop the sauce from burning, for 5 minutes, or until the sauce becomes thick and sticky. Remove pan from heat and leave sauce to cool for 5 minutes.
3 Stir baked-bean sauce into reserved vegie mash. Add egg and breadcrumbs; mix well.
4 Heat 1 teaspoon of oil in a large, shallow non-stick frying pan set over low heat. Wet hands to form bean mixture into four large patties. Smooth edges with spoon. (Note: Patties will be soft.)
5 Add patties to pan and cook (flipping patties very carefully to stop them from falling apart) for 4 minutes per side, or until patties are golden brown.
6 Mix yoghurt and cumin in a small bowl. Fill each roll with radicchio, cucumber ribbons, a bean patty and a spoonful of cumin–yoghurt mixture; serve.