Chop onion and cook in a pan coated with olive oil until fragrant and tender.
Add the carrots and cauliflower to the pan and cook until tender, but don't let them get too mushy.
Make a flax egg by adding 1 tbsp flax and 2 tbsp water to a small bowl and let it sit for 1-2 min.
Add all of your ingredients to a blender and blend until almost smooth, but leaving some texture if desired.
Form mixture into 6-8 patties depending on how small or big you want them.
Heat a non stick pan with some olive oil and fry patties for 2-3 min on each side, or until golden brown.
Serve patties on burger buns with favorite toppings!
These can be stored in fridge in an air tight container for up to 5 days.