Heat 2 teaspoons oil in a large non-stick frying pan. Add onion and cook, stirring, for 5 minutes or until softened. Add cumin and cook, stirring, for 1 minute or until fragrant. Remove pan from heat.

Place cannellini beans in a large bowl and mash, leaving some texture. Squeeze excess moisture from beetroot, then add to mash, along with cooled onion mixture, cooked quinoa, egg, parsley and 80g feta. Mix well to combine. Shape mixture into four 2cm-thick patties. Place quinoa flakes on a large plate. Press patties into flakes to lightly coat.

Heat remaining oil in a large non-stick frying pan over medium-high heat. Add patties and cook for 3 minutes each side or until golden and cooked through. Meanwhile place tahini and lemon juice in a small bowl. Add a tablespoon of warm water and combine until smooth.

Spread mashed avocado on roll bases. Top each with a beetroot and quinoa patty, then tomato, carrot, rocket and microherbs, if using. Drizzle over tahini dressing, crumble over remaining feta, then serve burgers sandwiched with roll tops.