Preheat the oven to 170°C
Tip the black beans onto a baking tray in a single layer and roast for 20 minutes to dry them out with no oil or seasoning
Set the roasted beans aside to cool slightly
Fry the diced onion in a little oil over medium heat until soft and deeply golden, about 10-12 minutes, then season well
Add the roasted beans, cooked onion, sun-dried tomatoes, smoked paprika, cumin, ketchup, marmite, and Worcestershire sauce to a food processor along with salt and black pepper
Blitz until mostly combined with some texture remaining, not a puree
Add the breadcrumbs last and pulse briefly to bring it together into a scoopable dough
Divide and form into 8 patties (around 70-75g each), pressing firmly to hold their shape
Press between two squares of parchment and smooth the edges to neaten up
Cover and chill if you have time
Cook in a lightly oiled pan over medium heat until golden, around 2 minutes per side
