Peel and cube the sweet potato. In a large non-stick pan heat up approx. ½ tbsp of oil, add the sweet potato along with the spice mix and stir.
Cook over a medium heat for about 10-12 minutes stirring occasionally until nicely browned and tender (but not cooked completely, still a little al dente). Remove from the heat and set aside to cool a little.
To the blender add all the burger ingredients (including the sweet potato, which can still be a little warm). If using miso paste combine it with the tomato puree before adding to the blender.
Pulse until the mixture starts coming together but there are still pieces of vegetables visible (be careful not to overblend it).
Form 4 burgers. Make sure you press the mixture together well so the burgers hold their shape.
In a large pan heat up 1 tablespoon of oil and fry the burgers over a medium heat for about 2 minutes on each side until lightly browned (add a little more oil after turning them over). Serve with your favourite burger bun.
Peel then weigh the sweet potatoes.
Cook the sweet potato al dente (it should be tender but still with a little crunch, not fully cooked).
Taste the mixture and adjust the seasoning as required before forming the burgers. I added a small amount of salt, but you may not need to add any.
It’s best to fry the burgers as soon as you’ve formed them.