Wash potatoes and cut into bite-sized pieces. Add to a pot, add salt, and cover with water. Bring to a boil, lower heat, and leave to simmer for approx. 15 min. In the meantime, roughly chop rosemary and parsley, dice onion, and slice sun-dried tomatoes into strips. Drain beans.
Preheat oven to 190°C/275°F. Add breadcrumbs, rosemary, parsley, onion, sun-dried tomatoes, and drained beans to a bowl and mix to combine. Set aside. Once potatoes have cooked, mash with a potato masher until mostly smooth with some small lumps.
Line a baking sheet with parchment paper. Add mashed potatoes and breadcrumb mixture to a food processor and process until well incorporated. Mixture should be sticky. Form mixture into 6 patties using your hands and add to prepared baking sheet. Season each patty with red pepper flakes, salt, and pepper. Transfer to preheated oven and bake at 190°C/275°F for approx. 15 min., flipping halfway through. Remove from oven and let cool for approx. 5 min.
Serve as a sandwich with some leafy greens and Dijon mustard on whole grain wheat bread. Enjoy!