Slice three-quarters of it into ½cm rounds and place in a large non-stick frying pan on a medium-high heat with 1 tablespoon of olive oil to soften and char, turning after a few minutes.
Meanwhile, coarsely grate the remaining sweet potato and the cabbage.
Mix with the mustard and 1 tablespoon of red wine vinegar to make a slaw, then season to perfection.
Scrunch up the minced beef, divide into two and shape into patties, then season with sea salt and black pepper.
Fry alongside the sweet potato slices for 3 minutes on each side, or until cooked through, brushing with the BBQ sauce for the final minute.
Halve and lightly toast your buns, then pile on the slaw and add a few lettuce leaves.
Arrange the charred sweet potato slices on top, then add the burgers and cottage cheese.