1.Preheat oven to 200°C. Line a large oven tray with baking paper.
2.Process chickpeas, onion, almond meal, egg, harissa, cumin and baking powder to form a chunky paste; season. Transfer half the mixture to another bowl.
3.To make beetroot patties, use your hand to squeeze any excess liquid from beetroot; add flesh to processor. Pulse to combine. Divide beetroot mixture in half; shape into two patties. Place on a tray lined with baking paper.
4.To make broccoli patties, process broccoli and spinach until chopped finely; add to reserved chickpea mixture. Divide broccoli mixture in half; shape into 2 patties. Place on tray alongside beetroot patties; spray with olive oil. Bake patties for 25 minutes or until firm and lightly browned.
5.Make rocket aïoli. Process ingredients in a small food processor until smooth and well combined. Transfer to a small bowl; season to taste.
6.Heat a non-stick frying pan over medium heat; add buns, cut-side down. Toast for 2 minutes or until light golden. Transfer buns to plates. Spread cut sides of buns with aïoli. Place a pattie on each bun base.
7.Top patties with slaw and a spoonful of rocket aïoli. Cover patties with bun lids; serve.
The patties can be pan-fried over medium heat; but take care when turning, as the mixture is quite soft, which is what gives the patties their lovely texture.
Replace beetroot with carrots and broccoli and spinach with cauliflower and ¼ cup grated vegetarian cheddar, if you like.