In a medium frying pan, heat 2 tablespoons vegetable oil. Add onion, garlic and mushrooms, season and fry on medium heat for about 5 minutes until everything is soft, pour all of these into a large mixing bowl.
Pour the sweet potato into a microwaveable bowl, and cover the bowl and microwave it for 5-6 minutes until it becomes soft on high heat. Cool the sakarkand slightly.
Mash the sweet potato in the same microwavable bowl, then add to the bowl with a mixture of onion, garlic, mushrooms. And leave to cool.
Now after cooling, add quinoa, beetroot, egg, coriander, lemon zest, flour, and some spices. And mix well with your hands, when all the spices and vegetables are mixed well.
Then make four big burger patis. Sprinkle some flour over the burger patis, and leave to cool for about 30 minutes.