Make flax egg and set aside. Place the first four ingredients into bowl of food processor and blend until the leaves and onions are chopped finely. Now add in the next 5 ingredients and pulse several times, so some lentils stay whole (you don't want to turn this into a dip!). Transfer to a mixing bowl and add in flax egg and combine. Now add in flour and mix throughly using a wooden spoon. Preheat a pan with a little bit of olive oil, and shape the patties. Over medium-high heat bake for four minutes, flip and press the burger down gently and bake for another three minutes. Serve with some sweet potato fries and you've got yourself a veganized and healthy american dinner :)